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PRINCIPLES OF PLANT CULTURE 



AN ELEMENTARY TREATISE DESIGNED AS A 
TEXT-BOOK FOR BEGINNEBS IN AGRI- 
CULTURE AND HORTICULTURE 



BY 

E. 8. GOFF 

Professor 01 Hortici i/turs m thh UmvBRSitTf of Wisconsin 



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'&*' 



PUBLISHED BY THE AUTHOR 
1897 



Copyright, 1897 
By E. S. GOFF 



M. J. Cantwell, Printer 
Madison, Wis. 



PREFACE. 



This book has grown out of the author's experience in 
the lecture room and laboratory, while giving instruction 
to students in the Short Course in Agriculture, in the 
University of Wisconsin. 

It is intended especially for students who have had little 
or no previous instruction in botany, and it is hoped that it 
may also be found interesting and profitable to the general 
reader who would learn more of the principles that underlie 
the culture of plants. 

It is expected that the instructor will amplify the text 
in proportion to the time at his command, and the capacity 
of his students. In the author's practice, the first three 
chapters have been found sufficient for a term of twelve 
weeks, and the remaining chapters, supplemented with some 
special work in horticulture, have served for a second term. 

A syllabus of laboratory work is added as an appendix. 

It is hoped that this book may prove as useful to other 
instructors as it has proved to the author during its 
evolution. 

Madison, Wis., Feb. 15, 1897. E. S. GOFF. 



ACKNOWLEDGEMENTS. 



The author desires to express his thanks to Prof. Charles 
R Barnes, of the University of Wisconsin, Prof. F. W. Woll, 
of the Wisconsin Agricultural Experiment Station and Mr. 
F. Cranefield, the author's assistant in horticulture, for 
revision of the manuscript, and for many valuable sugges- 
tions. 

Figures 12, 13, 16, 17, 18, 19, 20, 26, 27, 28, 32, 44, 45, 
46, 47, 51, 52, 53 and 82 were copied from " Agricultural 
Botany ", with the sanction of the author, Prof. M. C. 
Potter, of the Durham College of Science, England. Figures 
60, 61, 62, 81, 83, 96, 97, 99, 100, 101, 102, 112, 116, 117, 
118, 119, 120, 122 and 126 are from "The Nursery Book ", 
by Prof. L. H. Bailey, and are used by permission. Figures 
29, 58,80, 84, 98 and 129 are from "The Amateur Fruit 
Book, by Prof. S. B. Green, and are used by permission. 
Fig. 30, is from a photograph kindly loaned by Prof. Green. 
Figures 35, 37, 38, 39, 40 and 42 are copied by permission 
of the publishers from " Barry's Fruit Garden ". Figures 
93 and 94 are from "How to make the Garden pay ", by 
T. Greiner, and are used by permission. Figures 64 and 
65 were copied by permission from Bulletin No. 37, of the 
Rhode Island Agricultural Experiment Station. Figures 
74, 75 and 76, are from cuts in the possession of the Wis- 
consin Agricultural Experiment Station. 



CONTENTS. 



Page. 

Chapter I.— Introductory 9— 20 

Chapter II —The Round of Plant Life 21—109 

The Behavior of Seeds toward Water 21— 23 

Germination 23 — 31 

The Plantlet 31— 46 

The Inner Structure of the Plantlet 46— 54 

The Water of Plants and its Movements. 55 — 61 

The Root and the Soil 62— 75 

The Stem 75— 78 

The Leaves 78— 81 

The Buds 82— 90 

The Flower 90— 98 

The Fruit and the Seed 98—100 

The Gathering and Storing of Seeds 100—105 

The Decline of Growth and the Rest 

Period 105—109 

Chapter III. — The Plant as Affected by Unfavorable En- 
vironment 110 — 174 

The Plant as Affected by Unfavorable 

Temperature 110—119 

A— by Excessive Heat 110—113 

B— by Excessive Cold 113—119 

Methods of Averting Injury by Cold 119—127 

A— During the Dormant Period. ...119— 120 
B— During the Growing Period. ...121— 127 
The Plant as Affected by Unfavorable 

Water Supply 127—134 

A— By Excessive Water 127—131 

B— By Insufficient Water 131—134 



8 Contents. 

Page. 
Chapter III.— The Plant as Affected by Unfavorable 

Light 134—138 

A— By Excessive Light 134—136 

B— By Insufficient Light 136—138 

The Plant as Affected by Unfavorable 

Wind 138—139 

A — By Excessive Wind 138 

B— By Insufficient Wind 139 

The Plant as Affected by Unfavorable 

Food Supply 140—147 

A—By Excessive Food 140—141 

B— By Insufficient Food 141—147 

Plants as Injuriously Affected by Par- 
asites 147—172 

A — By Animal Parasites 148 — 164 

B— By Vegetable Parasites 164—172 

The Plant as Affected by Weeds 172—174 

Chapter IV— Plant Manipulation 175—248 

Plant Propagation 175—218 

A— By Seeds 176-177 

B — By Division, i. e., \>y parts 

other than Seeds 177—218 

Transplanting 218—234 

A— Lifting the Plant 219—221 

B— Removing the Plant 221—223 

C— Replanting 224—232 

D — After Care of Transplanted 

Stock 232—234 

Pruning 234—248 

A — Formative Pruning 237 — 242 

B— Stimulative Pruning 242—246 

C — Protective Pruning 246 

D — Maturative Pruning 246 

Chapter V.— Plant Breeding 249—258 



PRINCIPLES OF PLANT CULTURE 



CHAPTER I. 
INTRODUCTORY 

Before taking up a systematic study of plant culture, we 
may profitably consider a few principles of a more general 
nature. 

1 . The Difference between Art and Science. Art is 

simply knowing how to do a thing without reference to 
reasons. Science considers the reasons for doing it in a 
particular manner. Art implies more or less of skill gained 
through practice. Science implies a knowledge of the ob- 
jects to be gained by a given operation and the conditions 
affecting the process. 

An intelligent but ignorant person might be taught to 
prepare and insert a cion (386)* in the most approved manner. 
This pertains to the art of grafting. The same person 
might be taught the reasons why each step of the process is 
performed in its particular manner. This pertains to the 
science of grafting. One may become a skilled grafter 
without learning the science of grafting, but he cannot 
graft intelligently. The artisan, however skillful, who knows 
only the art, cannot become a master workman in the highest 
sense until he learns also the science that underlies his trade. 



* The numbers in parenthesis in the text refer to the numbered paragraphs in 
this book, and are intended to help students to a better understanding of the 
subject, 



io Principles of Plant Culture. 

The art of doing any kind of work is best learned In- 
working under the guidance of a skilled workman. The 
science is best learned from books or through trained in- 
Btructors. This book aims to teach the science rather than 
the art oi' plant culture. 

% 2. The Application of Knowledge is as essential to 
success in any vocation as the knowledge itself. The 
cultivator must supplement his knowledge with sufficient 
energy to apply it in the proper place^ the proper manner and 
at the proper time.ov the highest success cannot be expected. 

3. Environment is a term used to express all the out- 
side influences, taken as a whole, that affect a given object 
in any way. A plant or animal, for example, is affected by 
various external conditions, as heat, moisture, light, food. 
etc. These conditions and all others that iufluence the plant 
or animal make up its environment. 

4. What is Culture ? The well-being of a plant or 
animal depends very much upon a favorable condition of 
environment, and with the proper knowledge, we can do 
much toward keeping the environment in a favorable con- 
dition. For example, if the soil in which a plant is rooted 
lacks plant food, we can enrich it; if it lacks sufficient 
moisture, we can dampen it; if the plant is shaded by weeds. 
we can remove them. These, and any other things that we 
can do to make the environment more favorable, constitute 
culture in the broadest sense of the term. A full knowledge of 
the culture of any plant implies a knowledge, notonl}' of the 
plant and its needs, but of each separate factor in its envi- 
ronment, and how to maintain this factor in the condition 
that best favors the plant's development toward some special 
end, as the production of fruit, flowers or seed, of the finest 



Introductory. 1 1 

and highest type. We should know, not only the soil that 
best suits the plant, hut the amount of air, light, moisture, 
warmth and food in which it prospers best. We should 
know the enemies that prey upon it, the manner in which 
the} 7 work their harm, and how to prevent their ravages. 
We should know, in short, how to regulate every factor of 
environment so as to promote the plant's well-being to the 
utmost, as well as how to develop every desirable quality the 
plant possesses. 

5. Domestic or Domesticated Plants or Animals 

are those that are in the state of culture. In nature, differ- 
ent plants and animals struggle with one another for space 
and food. Only those best adapted to their environment 
survive, and these are often much restricted in their devel- 
opment. In culture, the intelligence and energy of man 
produce a more favorable environment for the species he 
desires to rear: hence domestic plants and animals attain 
higher development in certain directions than their wild 
parents. The cultivated potato, for example, grows larger, 
is more productive and is higher in food value than the wild 
potato. The finer breeds of horses and cattle are superior 
to their wild progenitors in usefulness to man. 

0. Culture Aims to Improve upon Nature's Methods 

rather than to imitate them. By cutting out the superfluous 
branches from a fruit tree, we enable the fruit on the re- 
maining branches to reach a higher state of development. 
By planting corn at the proper distances, we prevent crowd- 
ing, and enable each plant to attain its maximum growth. 
We should constantly study nature's methods for useful 
hints, but the highest progress would be impossible if we 
sought only to imitate nature. 



12 Principles of Plant Culture. 

7. Culture Deals with Life. All the products of cul- 
ture, whether obtained from the farm, garden, orchard, 
nurseiy or green-house, proceed directly or indirectly from 
plants or animals, both of which are living beings. A 
knowledge of the conditions that sustain and promote life, 
is, therefore, the foundation to a broad knowledge of hus- 
bandry. 

8. What is Life ? We know nothing of life except as 
it is manifested through the bodies of plants and animals. 
Within these, we can define, within certain limits, the range 
of environment in which it can exist; we can hinder or 
favor it; we can destro} 7 , but we cannot restore it. We 
know that it proceeds from a parental body similar to its 
own, that the body it inhabits undergoes a definite, progress- 
ive period of development, at the end of which the life dis- 
appears and the bod} 7 loses more or less promptly its form 
and properties. 

9. Vigor and Feebleness are terms used to express 
the relative energy manifested by the life of different living 
beings. Certain trees in the nurser} 7 row usually outstrip 
others in growth, i. e., are more vigorous than others. One 
pig in a litter very often grows slower than any of the 
others, i. e., is more feeble or less vigorous than any of the 
others. Feebleness is the opposite of vigor. The most 
vigorous plant or animal usually attains the largest size, and 
as a rule, is most satisfactory to its owner. . Vigor is pro- 
moted by a favorable environment. It is usually greatest 
in rather young plants and animals, and declines with ad- 
vancing age. It may be reduced by disease or improper 
treatment, and when thus reduced is often difficult to re- 
store. Reduced vigor often tends to early maturity and 
shortened life, and sometimes to increased prolificacy. 



Introductory. 



*3 



10. Hardiness and Tenderness are terms used to ex- 
press the power possessed by different plants or animals to 
endure extremes in their environment. The Oldenburgh 
apple endures without material harm vicissitudes of tem- 
perature that are fatal to many other varieties; in other 
words, it is hardier as regards temperature, than man} y 
other varieties. The reindeer is hardier as regards cold than 
the elephant, but tenderer as regards heat. The melon plant 
is hardier as regards heat and drought than the lettuce, but 
tenderer as regards wet or cold. 

11. Health and Disease. A plant or animal is said 
to be in health when all its organs (parts) are capable of per- 
forming their normal functions. An organ incapable of 
doing this, or the being possessing such an organ, is said to 
be diseased. 

12. The Cellular Structure of Living Beings. A 
bit of vegetable or animal substance, examined under a 
microscope of moderately high power, is seen to be made up 

of numerous little sacks or cav- 
ities, more or less clearly de- 
fined, called cells. Cells from 
different beings, or from differ- 
ent parts of the same being, 
may vary much in form and 
size, but they are seldom large 
enough to be seen without mag- 
nifying power. Some of the 
lowest plants and animals con- 
sist of single cells (Fig. 1). 
Some of the lower plants con- 
sist of a single row of cells united at the ends (Fig. 2). 




B 





Fig. 1. Showing four individual 
plants of a species of Protoccus. A 
shows a plant before commencing 
to divide into other plants. B. C. 
and D show how the cells divide to 
form other plants. Highly magni- 
fied. 



H 



Principles of Plant Culture. 



The higher plants and animals are made up of many cells 
united, and in these, the cells assume different forms and 
properties in the different organs (Fig. 3). In some cases, 



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Fig. 2. Part of a filament of a species of Spirogyra, a plant consisting of a 
single row of cells united at their ends. The places where the cells join are indi- 
cated by the vertical lines. Highly magnified. 

the united cells may be readity separated from one another, 
which shows each cell to be more or less an independent 
structure. As a rule, each cell is surrounded by its own 
closed cell-wall. 

13. Protoplasm (pro'- 
to-plasm). Living cells con- 
sist of a transparent, jelty- 
like substance called protop- 
lasm, which manifests the 
various phenomena of life. 
Protoplasm may exist either 
in an active or dormant 
state. In the active state 
it requires both nourishment 
and oxygen; in the dormant 
state it may exist for a con- 
siderable time without either, 
and is far less susceptible to . FlG 3> showin g cells of the a PP le le » f 

in a section from its upper to its lower 
external influences than in surface. Highly magnified. The spaces 

its active state. The protop- marked T are cavities between tbe cells ' 
lasm contained in plants during their rest period (172), in 
mature air-dry* seeds, and in the lower animals during their 
torpid condition is in the so-called dormant state. 

* Material is said to be " air-dry " when it is as dry as it will become by expo- 
sure to the air at ordinary temperatures. 




^QoefeG 



Introductory. 1 5 

14. Reserve Food. Active protoplasm may absorb 
nourishment in excess of immediate requirements and hold 
it as reserve food. In plants, this reserve food is in the form 
of starch, sugar or oil; in animals it is in the form of fat. 
These substances are formed by the protoplasm from its 
crude food materials through a process known as assimila- 
tion (59). The reserve food enables the plant or animal to 
live through limited periods of scarcity, and to meet the de- 
mands necessitated b}^ reproduction (16). 

15. Growth is the permanent change in form of a living 
vegetable or animal body, and is usually accompanied by in- 
crease in size. It may occur either through increase in size 
of cells already formed, or through cell multiplication. The 
latter may take place either by division of older cells into 
two or more smaller cells (Fig. 1), or by the formation of 
new cells within older ones, — the young cells thus formed 
attaining full size by subsequent expansion. 

16. Reproduction is the multiplication of living indi- 
viduals. It is one of the properties of protoplasm. As 
living cells containing protoplasm multiply by forming new 
cells, so living beings, which consist of cells, multiply by 
the separation of a part of their own cells, and this separa- 
ted group of cells grows into a complete organism like the 
parent. The higher plants multiply by seeds (156), which 
are separated from the parent plant, and each of which con- 
tains a young plant already formed within it (54). The eggs 
from which young birds are hatched contain cells filled with 
living protoplasm, and the protoplasm of the living young 
of mammals is separated from the parent before birth. 

17. Reproduction is either Sexual or Non=5exual. 

Sexual reproduction can take place only upon the union of 



16 Principles of Plant Culture. 

cells of different sexes. It is not peculiar to the animal 
kingdom, but occurs in plants also, and except in rare cases, 
is necessary to the production of seeds that are capable of 
germination (28). It is the only method of reproduction in 
the higher animals. Non-sexual reproduction is independent 
of sex. It results from the direct separation of a part of 
the parent, which under favorable conditions develops into a 
complete individual. It occurs when plants multiply by means 
other than by seeds, as by non-sexual spores (53). bulbs (352), 
stolons (348), cuttings (358), etc.. and it is a common method 
of reproduction in certain of the lower animals, as plant lice, 
(aphida?). Reproduction does not usually take place until 
the period of most rapid growth has passed. 

18. Heredity and Variation. The offspring of a plant 
or animal tends to be like the parent or parents. But no 
two beings can be begotten and developed in exactly the 
same environment, and since environment alwa} T s affects the 
individual more or less, it results that no two individuals can 
be precisel}' alike. Variation in the offspring ma} T take 
place in any direction, as in the size or color of the flower, 
the tenderness or juiciness of the fruit, the prolificac}\ the 
vigor (9), or the hardiness (10), etc. It follows, that in cul- 
ture, certain individual plants or animals are more desirable 
to the cultivator than others, because the individuals possess 
different qualities. 

19. The Principle of Selection. Since the offspring 
tends to resemble the parent or parents, b}' selecting the 
most desirable individuals for reproduction, we may gradu- 
ally improve plants or animals in the direction of greater 
usefulness. For example, b} T saving and planting seeds from 
the plants that produce the finest petunia or pansy blossoms, 



Introductory. 1 7 

we secure finer flowers than if we gather seeds without re- 
gard to parentage. 

20. Breeding in plants and animals is reproduction, 
watched over and directed by man, with reference to securing 
special qualities in the offspring. It is based on the princi- 
ple that the peculiarities of the parent or parents tend to 
be reproduced, and ma}- be intensified, in the descendents. 
But before we are prepared for the study of breeding, we 
need to know something of the principles of classification. 

21. Classification is the arrangement of the different 
kinds of plants and animals into groups and families based 
on individual resemblances. If we examine plants as they 
are growing in nature, we may observe a, that there are 
man}' plants of the same kind, and 6, that there are many 
kinds of plants. The different plants or animals of the 
same kind are called individuals, and, in general, we may say 
that the different kinds of plants or animals are called 
species (spe'-cies). But these simple distinctions are not suffi- 
cient to satisfy the needs of natural histoiy. We might say> 
for example, that the violet is one kind of plant and the oak 
is another, which is true: but there are also different kinds 
of violets and different kinds of oaks. We might sa} T that 
the apple is one kind of plant and the pear is another, but 
there are different kinds of apples, as the crab apple and the 
common apple, and there are different kinds of crab apples, 
and of common apples. We must not only arrange the 
kinds of plants into groups, but we must have groups of 
different grades. For example, botanists call each distinct 
kind of plant as the sugar maple, the white oak and the 
dandelion, a species. Then the species that rather closel} r 
resemble each other, as the sugar maple and the soft maple; 



1 8 Principles of Plant Culture. 

the white oak, the red oak and the bur oak; the raspberry 
and the blackberry; and the apple, pear and quince are 
formed into groups, each of which is called a genus, (ge'-nus), 
plural, genera, (gen'-e-ra). Then the genera that resemble 
each other, as the one containing the apple, pear and quince, 
and the one containing the plum, cherry and peach, are 
formed into other groups called families. * Thus families 
are made up of genera, and genera are made up of species. 
There may be, also, different varieties in the same species, as 
the different varieties of apple, pea or strawberry. 

An extensive retail bookstore furnishes an object lesson 
in classification, though we must remember that, in natural 
history, it is usually the names and descriptions of plants 
and animals that are classified, and not the plants and ani- 
mals themselves. In the bookstore, we will observe that 
the books are not placed upon the shelves without order, but 
that they are arranged in groups. Different copies of the 
same work are placed together. Different works on the same 
subject, as Gray's botany, Wood's botany, Bessey's botany 
are also placed in a larger group. Then all the scientific 
books are formed into a still larger group, as are the books 
of fiction, the books of poetry, the music books, etc. Com- 
paring this arrangement with that employed in natural his- 
tor} T , each separate work, as Gray's Manual of Botany, 
Thomas' Fruit Culturist, Bunyan's Pilgrim's Progress, etc., 
would correspond to a species, and the different copies of 
the same work would correspond to individuals. The books 
treating of the same general subject, as the different works 
on geology, botany or arithmetic would correspond to 
genera, and the different classes of books, as scientific 
books, books of fiction, etc., would correspond to families. 

* Groups of related families are often further united into orders. 



Introductory. 19 

There would also "be copies of the same work in different 
bindings which would correspond to varieties. 

22. Scientific Names are given to plants and animals 
because the common names by which they are known are so 
often local. For example, quack grass, one of our common 
troublesome weeds, is known by at least seven different com- 
mon names in this country alone, and yet, in a given locality 
it is often known by only one name. Its scientific name, 
however, Agropyrum repens (a-gro-py'-rum re'-pens), is the 
same in all languages and countries. Scientific names are 
usually Latin and consist of two words. The first word is 
the name of the genus to which the plant or animal belongs, 
and is called the generic (ge-ner'-ic) name; the second word 
designates the species, and is called the specific (spe-cif'-ic) 
name. For example, Pyrus malus (py'-rus ma'-lus) is the 
scientific name of the common apple, Pyrus being the genus 
to which the apple belongs, and malus designating which 
species of the genus is meant. 

23. Crosses and Hybrids (hy'-brids). We have seen 
(17), that in sexual reproduction, a union of male and female 
cells is almost always essential. When these cells proceed 
from two individuals of different varieties (21), the offspring 
is called a cross; when they proceed from individuals of differ- 
ent species, it is called a hybrid. Hybrids are possible only 
between closely allied species and are often incapable of re- 
production, in which case they are said to be sterile. The 
mule, which is a hybrid between the horse and the ass, is a 
familar example of a sterile hybrid. Sterile hybrids are not 
uncommon in plants. A hybrid that is capable of reproduc- 
tion is called a fertile hybrid. 



20 Principles of Plant Culture. 

Hybrids and crosses may resemble both parents about 
equally or they may resemble either parent more than the 
other. They sometimes differ materially from either parent. 
The offspring of crosses and fertile hybrids is generally 
variable in proportion as their parents were different from 
each other, and this variability may continue through several 
generations. 

24. The Theory of Evolution, now generalh' ac- 
cepted by naturalists, assumes that the higher plants and 
animals have been gradually evolved from lower forms, 
through the principle that those individuals possessing pecu- 
liarities best fitting them to endure the adverse conditions 
of environment have survived and perpetuated their Kind, 
while others have perished. 

25. Parasites. Both plants and animals are subject 
to being preyed upon by other, usually smaller, plants and 
animals, that live upon or within their bodies, consuming 
the tissues of their bodies or their reserve food. Plants or 
animals that derive their nourishment from other plants or 
animals are called parasites (par'-a-sites) or parasitic. The 
plant or animal from which a parasite derives its nourish- 
ment is called a host. Parasites are often microscopic in 
size. The}' are generally more or less injurious to their 
host, and form one of the most fruitful sources of disease. 
Some, however, as the bacteroids of the roots of clover 
(113) and other leguminous plants, are beneficial. 



CHAPTER II. 

THE ROUND OF PLANT LIFE 

The earliest stages of plant growth occur in the seed, 
hence this is an appropriate place to commence our stud}'. 
We will first consider 

Section I. The Behavior of Seeds Toward Water 

26. Seeds Absorb Water when Placed in Contact with 
it. If we fill a bottle with air- dry beans, then pour in all 
the tepid water the bottle will contain, taking care to shake 
out the air bubbles, and place the bottle in a waim room, 
the beans will soon swell until they have pressed each other 
quite out of shape, forcing no water from the bottle in the 
meantime. This shows that the beans have absorbed the 
water and have swollen in consequence. This quality of 
absorbing water by contact, at ordinary temperatures, is 
possessed to a greater or less extent by most seeds, and in- 
deed by nearly all air-dry vegetable material. It is un- 
necessary that the seeds be covered with water to enable 
them to absorb it. If in contact with an} T moist medium, as 
a damp cloth or damp earth, they will absorb moisture and 
swell. 

27. The Rate at which Seeds Absorb Water depends 
upon several conditions, as 

(a) — The water content of the medium with which they are 
in contact. If we place one lot of beans in water, a second 
in wet earth and a third in slightly damp earth, we shall find. 



2 2 Principles of Plant Culture. 

that the first lot will swell fastest, the second next and the 
third slowest. Few seeds will absorb enough water from 
damp air at ordinary temperatures to swell much. 

(b) — The points of contact. If we weigh, on a delicate 
balance, two lots of 100 beans each, and mix each lot with 
well-crumbled, moist loam, in a fruit jar, packing the loam 
down tightly in one of the jars and leaving it loose as possi- 
ble in the other, close both jars to prevent evaporation, ami 
after twenty-four hours sift the beans out of the loam and 
weigh the two lots again, we shall find that the beans in the 
jar containing the compacted loam have increased in weight 
more than the others. This indicates that the beans in this 
jar have absorbed water taster than those in the other, be- 
cause they were in contact with the moist loam at more 
points. 

(c) — Temperature. If we fill two bottles with beans, add- 
ing ice water to one, placing it in a refrigerator, and luke- 
warm water to the other, setting it in a warm room, we shall 
find that the beans in the latter bottle will swell more rap- 
idly than those in the former. This shows that a warm 
temperature favors the absorption of water — a fact that is 
true of all seeds. The same would have been true had we 
planted the beans in two samples of moist earth, placing 
these in different temperatures. 

(d) — The nature of the seed-case* In the bean, Indian 



* The term seed-case is here used to designate the outer covering of the seed 
as the word seed is understood by the seednian or planter. Every seed, as we buy 
it in the market, or when ready for planting, lias one or more covering layers. In 
the peanut, for example, what we here call the seed-case is eommouly called the 
shuck; in the cocoauut it is called the shell; in the bean and Indian corn it is more 
often called the skin. In botany, the outer coverings of seeds are given different 
names, as pericarp, testa, etc, according to their exact office in the make-up of the 
plant. To avoid explaining the technicalties of a complex subject, it seems prefer- 
able to adopt a term that will include the various words used in botany to designate 
the outer coverings of seeds. 



Germination. 23 

corn, wheat and many other seeds, the seed-case is of such 
a nature that it absorbs and transmits water readily. In 
certain seeds, however, as the honey locust, canna, thorn 
apple, etc., especially if they have been allowed to become 
dry, the seed-case does not readily transmit water at ordin- 
ary growing temperatures. Such seeds may lie for weeks, 
and even months, in tepid water without swelling, but when 
the water is heated to a certain degree, they swell promptly, 
a fact often turned to account by the nurser} r man. We 
cannot always judge by the appearance of a seed-case 
whether it will transmit water readily or not. 

Section II. Germination 

28. What is Germination? If we place a few grains 
of mature Indian corn that are not too old to possess vital- 
ity (165), between the well-moistened cloths of a seed- 
tester (Fig. 5), cover with the glass and place in a warm room, 
we shall observe, if we examine the corn frequently, that a 
change, aside from the swelling, will soon take place in at 
least a part of the grains. The seed-case will be bursted by 
the pressure of a tiny white shoot from beneath. We say 
that such grains have sprouted or have commenced to ger- 
minate (ger'-mi-nate), i. e., have taken the first visible step 
toward developing into a plant. 

We have seen (13) that the mature seed contains protop- 
lasm in its dormant condition. On the absorption of water, 
with a suitable temperature, the protoplasm resumes its 
active state, and the cells of a certain part of the seed begin 
to increase in number by division (15), causing the tiny 
shoot to burst through the seed-case. Germination is com- 
pleted when the young plant (plantlet) is sufficiently devel- 
oped to live without further assistance from the seed. 



24 Principles of Plant Culture. 

29. Moisture is Essential to Germination. Air-dry 
corn or other seeds will not germinate if kept however long 
in a warm room, whereas vital seeds, that have absorbed 
water until fully swollen, will usually germinate if exposed 
to air of a suitable temperature, under conditions that pre- 
vent their loss of moisture. This shows that a certain 
amount of moisture must be absorbed by the seed before 
germination can take place. Seeds must be nearly or quite 
saturated with water before they will germinate. 

In culture we plant seeds in some moist medium, usualty 
the soil, in order that they may absorb moisture and germi- 
nate, and thus develop into new plants. 

30. Warmth is Essential to Germination. Had we 

placed the seed-tester mentioned in paragraph 28 in a re- 
frigerator in which the temperature never rises above 46° F., 
instead of in a warm room, the corn grains would not have 
germinated however long they remained there. This shows 
that a certain degree of warmth is also necessary to germi- 
nation. Without this, the protoplasm of the seed cannot 
assume its active state (13). The lowest (minimum) tem- 
perature at which seeds can germinate varies considerably 
with different species, and so does the temperature at which 
they germinate soonest (optimum) as also the highest (max- 
imum) temperature at which the}' can germinate. The fol- 
lowing table* shows approximately the minimum, optimum 
and maximum temperatures at which seeds of the species 
named germinate. 



Compiled from Haberlandt and Sachs. 



Germination. 25 

MINIMUM. OPTIMUM. MAXIMUM. 

Bean (Scarlet runner) 49° F 77°-88° F 99°-lll° F. 

Barley 41 77 -88 88 -99 

Buckweat 41 93 115 

Clover (red) 88-99 99-111 Ill -122 

Cucumber 60-65 88 -99 Ill -122 

Flax 41 77 -88 88 -99 

Hemp 32-41 99 -111 Ill -122 

Indian corn 41-51 99-111 Ill -122 

Lucerne ( Alfalfa) S8-99 99-111 111-122 

Melon 60-65 88 -99 Ill -122 

Oat 32-41 77 -88 88 -99 

Pea 32-41 77-88 \ 88-99 

Pumpkin 51-60 93 -111 Ill -122 

Rye 32-41 77 -88 88 -99 

Sunflower ..41-51 88 -99 99 -111 

Wheat 32-41 77 -88 88 -108 

These temperatures refer to the soil or other medium 
with which the seeds are in contact, and not to the atmos- 
phere. 

When moisture is sufficient, the time from planting to 
sprouting decreases rapidly as we approach the optimum 
temperature. In an experiment, Indian corn sprouted in 
one-third of the time at 88° F. that it required to sprout 
at 61°. 

31. Free Oxygen is Essential to Germination. If 

we place in the bottom of each of two saucers* a layer of 
puddledf clay or loam, put 25 beans capable of germination 
on the soil in each saucer, then fill one saucer with moist 
sand, and the other with puddled clay or loam, pressing the 

* If flower-pot saucers are used they should first be well soaked in water, so 
that they will not extract water from the soil. 

f Soil is said to he puddled when wet and packed until it is in the consistency 
of putty. 
2 



26 Principles of Plant Culture. 

latter clown closely over the beans, cover both saucers with 
a bell glass, and place in a warm room for two or three days r 
we shall find that the beans covered with the sand will 
sprout prompt^, while those covered with the puddled soil 
will not (Fig. 4). In the sand-covered saucer the air has had 



Fig. 4. In the left hand saucer, beans were planted in puddled soil. In the 
other, they were covered with sand. They failed to germinate in the puddled soil,' 
because their contact with oxygen was cut off. (From nature). 

access to the beans between the grains of sand, while in the 
other the'air has been shut out, which explains the sprout- 
ing of one lot of seeds and the failure of the other. About 
one-fifth of the air is free oxygen, i. e., oxygen that is not 
chemically combined with an} T other substance. 

We have seen (13) that protoplasm in its active state 
requires ox} T gen. Unless seeds are so planted that a certain 
amount of this free oxygen can reach them they cannot 
germinate.* Ordinary water contains a little free oxygen, 
but not enough to enable man} T kinds of seeds to germinate 
in it, though the seeds of some water plants, as the water 
lily and rice will germinate in water. But evemthese will 
not germinate in water that has been boiled long enough to 
expel the oxygen, and placed under conditions that prevent 
the absorption of it again. 

We thus see that seeds require three conditions before 
they can germinate, viz., a certain amount of moisture, of 



* This probably explains why very deeply planted seeds rarely germinate. 



Germination. 27 

warmth and of ox}'gen. In planting seeds, we should con- 
sider all these requirements. 

32. Prompt Germination is Important. As a rule, 
the sooner a seed germinates after it is planted, the better, 
for it is generall}' in danger of being destroyed by animals 
or fungi, and the plantlet probably loses vigor by too slow 
development. Weeds may also be gaining a start if ger- 
mination is dela}'ed. We should, therefore, treat both the 
seed and the soil in the way that favors prompt germination. 

33. Compacting the Soil about planted seeds Hastens 
Germination by multiplying their points of contact with 
the moist earth (27). When the soil is becoming drier 
day by day, as it often is in spring, compacting the soil 
about planted seeds materially hastens their germination 
and often secures germination that without the compacting 
might be indefinitel} T postponed. The hoe, the feet, a board, 
or the hand or horse roller may be used to compact soil over 
planted seeds. 

34. Planting should be Deferred until the Soil be- 
comes Warm. Seeds cannot germinate promptly until the 
temperature of the soil in which they are planted ap- 
proaches the optimum for their germination (30) during 
the warmer part of the da} T , and germination is little, if at 
all, promoted by planting before this time. 

35. Excess of Water in the soil Retards Germina= 

tion by restricting the supply of ox}-gen (31), and some- 
times, b} T keeping the soil cold. Seeds should not be planted 
in soil wet enough to puddle (31) about them, nor should 
the soil in which the seeds of land plants are planted be so 
freely watered that the seeds remain surrounded with liquid 
water, thus shutting out the normal supply of oxygen. 



28 Principles of Plant Culture. 

36. Germination ma}- be Hastened by Soaking Seeds 

before planting. Since seeds cannot germinate until 
nearly or quite saturated with water (29), and since they 
absorb water faster from a very wet than from a damp me- 
dium (27(?)- and in a warm than in a cool temperature (27c), 
when the soil to receive the seeds is only slightly moist, we 
ma}' hasten germination a little by soaking the seeds, before 
planting, in warm or slightly hot water until they have 
swollen. The heated water not only penetrates the seed 
faster than cold water, but the heat appears to stimulate the 
protoplasm (13), so that increased vigor is imparted to the 
seedlings. This method is sometimes practiced by garden- 
ers with sweet corn and some other seeds, and its use might 
possibly be extended with profit. The water should not be 
heated to more than 110° to 120° F. and the soaking should 
be continued only until the seeds have full}' swollen. 

Soaking is more important with seeds having seed-cases 
that do not readily transmit water at growing temperatures, 
as of the honey locust, canna, thorn apple, etc., (21 d). Such 
seeds, particularly if they have been allowed to become dry, 
are generally soaked before planting in hot water until 
swollen, otherwise they might lie in the ground for months 
and even years before germinating. In treating such seeds 
to hot water, unless the temperature at which they swell is 
known, the water should be heated very gradually until the 
seeds begin to swell, when it should be maintained at that tern- 
perature until they are fully swollen. It is of interest that 
seeds of the honey locust may be immersed for a time in 
boiling water without destroying their vitality, but such 
treatment is not to be recommended for any seeds. In seeds 
of this class, 



Germination. 



29 



$7. Germination is sometimes Hastened by Cracking 
or Cutting Away part of the Seed=Case. To facilitate 
the absorption of water, nurserymen often drill or file a hole 
through the bony seed-cases of nelumbium seeds, or crack 
dry peach and plum pits, in a vise, or with an implement 
resembling a nutcracker (26c?). 

38. Seeds may Fail to Germinate from a variety of 
causes, even when exposed to the proper degree of warmth, 
moisture and oxygen. They ma}' be too old (165), they may 
not have been sufficiently mature when gathered (163), 
the}' may have become too dry (169), they may have been 
subjected to freezing before sufficiently dry (167), they may 
have been stored while damp, and thus subjected to undue 
heating, or they may have been damaged by insects or fungi, 
either before or after maturity. Defects of these kinds are 
not always discernible to the eye, hence 

39. Seeds should be Tested before Planting to learn 
if they will germinate. It is unnecessary to plant seeds in 
soil to test them, since the seed-tester shown in Fig. 5 is 




Fig. 5. Showing a simple seed-tester, adapted to farmers' and gardeners' use. 



3<d Principles of Plant Culture. 

much more convenient. This useful device consists of two 
circular pieces of moderately thick cloth, a table plate that 
is not warped, and a pane of glass large enough to cover the 
plate. The cloths are dipped in water, wrung out a little 
until moderately wet, spread over the bottom of the plate 
as shown, and the seeds to be tested are placed between 
them. It is well to use a hundred or more seeds of each 
sample, as a larger number will show the per cent, of vitality 
more accurately than a smaller one, and the lot should 
always be well mixed before taking the sample. The plate 
should be kept covered with the glass to prevent evapora- 
tion from the cloth, and it may be placed in any room of 
comfortable living temperature. The seeds should be fre- 
quently examined, and may be removed as they sprout, 
when by subtracting the number that fail to sprout from 
the number put in, the per cent, of vitality may be readily 
computed. The cloths should be placed in boiling water a 
few minutes before using them for a second test, to destroy 
any spores or mycelia of mold with which the}' ma}- have 
become infected. 

40. The Time Required for Germination varies 
greatly in different kinds of seeds. In lettuce seed, the tin} 7 
white shoot often breaks through the seed- case within 
twenty-four hours from planting, while celery seed requires 
several days to germinate to this extent. The seeds of 
many plants will not germinate the same season they are 
formed even if planted under the most favorable conditions. 

Individual seeds of the same kind and of the same sample 
often vary greatly in the time required for germination. 
Even in seeds that germinate soonest, as lettuce and radish, 
some individuals will not germinate until several days after 



The Plantlet. 31 

the majorit}* have germinated. Seeds of tobacco and purs- 
lane* sometimes continue to germinate through several suc- 
cessive seasons. The reasons for these great variations in 
the time required for germination are not well understood. 

Section III. The Plantlet 

By watching the germination of seeds, we ma} T learn some 
interesting facts. Good seeds will usually germinate freely 
on the surface of well-moistened soil or sand, if we provide 
a damp atmosphere above them by covering with a bell 
glass; for light does not hinder germination. One of the 
interesting facts connected with germination is, that the 
first shoot, called 

41. The Hypocotyl t (hy'-po-co'-tyl) Grows Down= 
ward, on emerging from the seed-case (72c?), no matter in 
what position the seed was placed. It will curve in a semi- 
circle if necessar3 T , to bring its rounded point in contact with 
the soil. But the hypocotyl is not alwa}'S able to enter the 
soil, unless the seed is covered more or less, because the 
resistance offered by the soil is often greater than the weight 
of the seed. On this account, as well as to insure a supply 
of moisture, it is always best to cover seeds at planting, or 
at least to press them well into the soil (52). In nature, 
most seeds become more or less covered, and those not cov- 
ered usually fail to germinate. 

42. The 5eed=Case in Germination. After germina- 
tion commences, the seed-case is of no further service. It 
has fulfilled its purpose, which is to protect the seed from 
the time of its maturity until the conditions arrive for ger- 

* Portulaca oleracea. 

f Often called radicle and caulicle. 



3 2 



Principles of Plant Culture. 



initiation. It is henceforth not only useless, but is a posi- 
tive hindrance to germination, in many plants, as it must 
be torn assunder by the expanding plantlet. If we examine 
germinating seeds of the squash or pumpkin, watching the 
germination process through its different stages, we may 
discover that, in these plants, nature has made a special 
provision to assist the plantlet in escaping from the seed- 
case. As the lrypocotyl curves downward, a projection or 
hook is formed on the side toward the seed, which holds the 
seed-case down while the seed-leaves are withdrawn from it. 
The action of this hook is shown in the accompanying fig- 





Fic. 6. Showing nature's provision to enable the pumpkin plantlet to escape 
from the seed-case. In A, the hook on the hypocotyl is attached to the lower half 
of the seed-case. B shows the same after germination is farther advanced. A 
fully germinated pumpkin plantlet is shown at Fig. 7. 

ures. Occasionally, as shown in C, the point of the seed- 
case breaks, permitting the hook to slip off, and if the seed 
happens to be planted edgewise, or with the point downward, 
the hook often fails to catch the seed-case, as in D, and so 
the plantlet emerges from the soil without freeing itself 



The Plantlet. 33 

from the seed-case and is hampered for a time. This pro- 
vision is peculiar to the pumpkin family,* to which the 
pumpkin, squash, cucumber and melon belong, though other 
provisions, which accomplish the same end, are found in a 
few other families, but many plants are considerably em- 
barassed by the seed-case during germination. 

43. Seeds of the Pumpkin Family should be Planted 
Flatwise, rather than edgewise or endwise, since in this 
position the} T most readity free themselves from the seed- 
case. 

44. Some Plantlets Need Help to Burst the Seed= 
Case. In many seeds having hard and strong- seed- 
cases, as the walnut, butternut and hickoiy nut and the pits 
of the plum, peach and cherry, the enlarging plantlet is 
often unable to burst the seed-case, hence germination can- 
not take place unless assisted b}^ the expanding power of 
frost, or long exposure to moisture, which softens the seed- 
case, or unless the seed-case is cracked before the seeds are 
planted (37). 

45. The Roots promptly start, as the h} T pocot3'l emer- 
ges from the seed-case, — the main (primary) root from its 
point, and the branch (lateral) roots from its side. Some- 
times root-hairs (101) may be distinctly seen, especially 
when seeds germinate in the seed-tester (39). 

By studying Figs. 7 to 10, we may learn more of the ger- 
minating process. 

46. The Cotyledons (co-ty-le'-dons). In the bean and 
pumpkin, the seed, or what remains of it, seems to have 
separated into two parts that are united at one end, — the 

* Cuourbitacete. 



34 



Principles of Plant Culture. 



cotyledons or seed-leaves. In the bean and pumpkin, the 
cot3 T leclons form a pair of very clums} T leaves, which in the 
bean, at first point downward, but afterward become up- 
right, b} r the straightening of the hypocotyl beneath them. 




Fig. 7. Plantlet Fig. 8. Plantlet Fig. 9. Plantlet Fig. 10 PlaDtlet 

of pumpkin. of bean. of Indian corn. of pea. 

In the pumpkin and bean, the seed-leaves (cotyledons) are lifted above the 
surface of the soil in germination. 

la the corn and pea, tne cotyledons are not lifted above the surface of the soil 
in germination. 

We observe that the pea has also a pair of cotyledons (c), 
that have not separated to the same extent as those of the 
bean and pumpkin, and are still beneath the soil. The 
corn, in common with other plants of its class, as sorghum, 
sugar cane, the reeds, grasses, etc., has but one cotyledon, 
and that is not easily made out without dissecting the seed. 
In Fig. 12, which shows a cross section of the germinating 
corn grain, the cotyledon appears at cot. 

The plants having two cotyledons form a ver} T important 
class in botany, known as Dicotyledones (di-co-tyl-e'-dones); 



The Plantlet. 



35 



those having but one cotyledon form a class known as Mo- 
nocotyledones (mo'-no-co-t3'l-e'-dones). There is also a class, 
including the pine, fir and other conifers, that have several 
cotyledons. 

4?. The Hypocotyl Develops Differently in Different 
Species. In the corn and pea (Figs. 9 and 10), the cotyle- 
dons remain in the soil, while in the beau and pumpkin. the} T 
have been lifted bodil}' into the air for a considerable dis- 
tance. This striking difference is due to the fact that in the 
corn and pea, the hypocotyl lengthens very little in germi- 
nation, while in the bean and pumpkin, it lengthens com- 
parative^ very much. 

48. Seeds in which the Hypocotyl Lengthens in ger- 
mination Must Not be Deeply Planted. When seeds of 

this class, which includes many 
plants beside the bean and pump- 
kin, are planted in the soil, the 
cotyledons must be forced through 
the soil above them, an act requir- 
ing considerable energ}\ If such 
seeds are covered with much soil, 
the plantlet is unable to lift its 
cotyledons to the surface, and 
hence it must perish. Fig. 11 
shows two bean plantlets that tore 
off their cotyledons in the vain 
attempt to lift them through five 
inches of soil. The plantlet of 
wheat, barle}' and oats, though 
much smaller and weaker than 
that of the bean, readily grows through this depth of soil, 
because the hypocotyl does not elongate in germination, and 




Fi<i. 11. Showing two bpan 
plantlets that tore otf their coty- 
ledons lroiu being too deeply 
planted. 



36 Principles of Plant Culture. 

hence the cotyledon is not lifted. The tin}' pointed shoot 
(plumule, 56) of these plants readily insinuates itself between 
the soil particles and comes to the surface, with little expend- 
iture of energy, even when deeply planted. Plantlets of the 
larger beans usually fail if the seeds are planted three 
inches deep in a clay soil that bakes above them. Those of 
the castor bean (Ricinus), though very robust, can hardty 
lift their cotyledons through one inch of soil, while those of 
the pea, though much more slender, readity grow through 
four to six inches. Apple seeds planted in autumn, on clay 
soil, usually fail to germinate the following spring, unless 
covered with sand or humus, or carefully mulched, because 
the plantlets are unable to lift their cotyledons through a 
baked surface soil. 

49. The Vigor of the Plantlet is general!}- in Propor= 
tion to the Size of the Seed. This is true, not only be- 
tween different kinds of seeds, but between different indi- 
vidual seeds of the same kind. The larger beans, the horse 
chestnut and the walnut form very much stronger plantlets 
than clover, timothy and tobacco, and the largest and 
plumpest specimens of any sample of seed usually form 
stronger plantlets than the smaller and more shrunken speci- 
mens. Growers of lettuce under glass are sometimes able 
to raise one more crop during the winter by sowing only 
the largest seeds than when the seed is sown without sift- 
ing. The practice of sifting seeds before planting, and re- 
jecting the smaller specimens, should be more generally 
followed. 

50. The Earlier Germinations from a sample of seed 
usually Form More Vigorous Seedlings than the Later 
Ones. This is nature's method of preserving the vigor of 



The Plant let. 37 

plants. The earlier seedlings overtop the later and feebler 
ones, and so crowd them out of existence. We should pro- 
fit by this hint and reject the later plants in the seed-bed. 

51. How Deep should Seeds be Planted? We have 
seen (29) that one object of planting seeds in the soil is to 
place them in contact with moisture. Since the plantlet 
must force its way through the soil that covers the seed, the 
less the depth of the soil, other things equal, the less energy 
and the shorter time are required for the plantlet to reach 
the surface. Therefore, seeds should not be planted deeper 
than is necessary to Insure the proper supply of moisture. 

Small seeds, as of lettuce, celery and carrot, produce such 
weak plantlets that it is unsafe to cover them sufficiently to 
insure the proper moisture supply in dry weather. We 
must, therefore, plant such seeds so early in spring that the 
soil has not had time to become dry, or if necessarifv planted 
later, we must depend largely upon artificial watering. 

52. Very Small Seeds, as of petunia and tobacco, 
Should Not Be Covered with soil at all, but may be pressed 
down into fine loam with a board or otherwise, and must be 
frequently and carefully watered with a watering-pot having 
a veiy fine rose. When small seeds are sown in full expos- 
ure to sunlight, it is well to shade the surface with paper or 
a muslin-covered frame, to check evaporation until the 
plantlets appear. Sometimes small seeds are covered with 
a very thin layer of sphagnum moss, that has been rubbed 
through a sieve. This helps to retain moisture in the sur- 
face soil. 

53. Ferns are Grown from Spores* sown on the sur- 



* Spores are the chief reproductive bodies in plants that produce no seed, as 
ferns, mushrooms, mosses, etc. They are usually so small as to be barely visible 



|8 



Principles of Plant Culture. 



face of fine soil in a propagating frame, in which the air is 
kept very moist and the surface of the soil never becomes 
dry. 

54. The Plantlet is Visible in the Seed. If we boil 
seeds of the four kinds shown in Figs. 7 to 10, or of other 
kinds, in water until they are fully swollen, and then care- 
fully dissect them with the forceps and needle, using the 
magnifying glass when necessary, we may observe that the 
plantlet is present, compactly folded up, in the seed. Ger- 
mination (28) is really little more than the unfolding and 
expansion of this plantlet. The plantlet, as it exists in the 
seed, is called the em&ryo' (em'-bry-o). 

55. The Endosperm* (en'-do-sperm). From the sec- 
tion of the corn grain shown in Fig. 12, it appears that, in 




Fig. 12. Cross section of germinating Indian corn grain. A. endosperm; 
Cot. cotyledon ; Caxi. hypocotyl ; PL plumule. Slightly magnified. (After Frank). 



to the unaided eye. The dust that escapes from a puff-ball when it is squeezed, 
or from a bunch of corn smut consists of the spores of these plants. Spores usu- 
ally consist of a single cell, in which respect they differ materially from seeds, 
which contain a more or less developed plantlet (54). 
* Called also albumen. 



The Plantlet. 39 

this seed, unlike the pea, bean and pumpkin, the plantlet 
and seed-case do not make up the whole bulk of the seed. 
The remaining part shown at A, consists mainly of cells 
containing starch grains and oil drops, which serve as food 
for the plantlet during germination, — since active pro- 
toplasm cannot exist without nourishment (13). In the 
pea, bean, pumpkin and other seeds of this class, the food 
supply, instead of being stored b} T itself, as in the corn- 
grain, is contained within the plantlet or embryo, — mainly 
in the flesh}- cotyledons. When the food supply of the seed 
is separate from the embryo, as in corn and many other 
seeds, it is called the endospurm. 

It is the food supply of the seeds that makes them so val- 
uable as food for animals. 

56. The Plumule (plu'-mule). If we look between the 
cotyledons of the bean plantlet, (Fig. 8), at the point of 
their union with the hypocot}i, we may see a pair of tiny 
leaves, and by carefully separating these, if need be, with 
the point of a pin, we may discover a minute projection, — 
the growing point (51) of the stem between them. These 
leaves, with the growing point, form the plumule, — the ter- 
minal bud of the plantlet. These tiny leaves become the 
first true leaves, and the growing point between them de- 
velops into the stem and later leaves. ~Ry close examination, 
we may make out the plumule in Figs. 7, 9 and 10. In the 
pea and corn, it has already made considerable growth. 

57. Thus we see that the plantlet or seedling consists of 
three parts, viz., the hypocot}^, the cotvledons (in some 
plants cotyledon) or seed-leaves, and the plumule or termi- 
nal bud. 



4° 



Principles of Plant Culture. 



58. Chlorophyll (chlo'-ro-phyll). Soon after the plant- 
let emerges from the seed-case, a green color appears in the 
parts most exposed to light. This green color is due to the 
formation within the cells of a substance known as chloro- 
phyll, — the green coloring matter of plants. Chlorophyll 
forms only in the light, and when a plant containing green 
leaves is kept for a time in the dark, as when celery is 
banked up with earth, the chlorophyll disappears, and the 
green parts become white. The chlorophyll saturates defi- 
nite particles of the protoplasm, called chlorophyll bodies, 
and since the cell- walls and protoplasm are transparent, in the 
younger cells, the chlorophyll bodies give the parts contain- 
er? ch 




Fig. 13. Showing cross section through leaf of Fagus sylvatica. Ch, chloro- 
phyll bodies ; Ep, epidermis of upper surface of leaf; Ep" , epidermis of lower sur- 
face ; K, cells containing crystals ; PI, palisade layer ; F, vascular bundle ; St, 
stoma; I, spaces between the cells, (intercellular spaces). Highly magnified. 
(After Strasburger). 

ing them a green color. Fig. 13 shows the distribution of 
the chlorophyll bodies in the cells of a portion of the leaf 
of the beech. They appear as minute globules, which in 
this case, are mostly located near the cell-walls. It will be 
seen that they are most numerous near the upper surface of 
the leaf, — the part most exposed to the sun's rays. 



The Plantlct. 



4 r 



59. No Food can be formed Without Chlorophyll. 

By the agenc} T of chlorophyll, the chlorophyll bodies absorb 
energy in the form of light. This energy the chlorophyll 
body uses to take to pieces the carbonic acid, mineral salts 
and water absorbed from the air and the soil, and to recom- 
bine them into foods of various kinds which can be used by 
the protoplasm in making new parts and in repairing waste. 
This process is known as Assimilation (as-sim'-i-la'-tion). 
Until assimilation commences, no neio plant substance has 
been formed. It is true that new cell-walls and new pro- 
toplasm maj T be formed from the food supply of the seed 
before chloroplrvll appears, but until chlorophyll is formed, 
and assimilation begins, the whole plantlet, with whatever 
remains of the seed, when dried, weighs no more than the 
seed weighed at the beginning. The material formed by 
assimilation is starch, or some substance of similar compo- 
sition (sugar or oil), which, after undergoing chemical 
changes, if need be to render it soluble, is distributed to 
other parts of the plant to be built up into cell-walls and 
protoplasm, or to be held as reserve food (14). 

Only plants can assimilate food from 
mineral substances. The food of ani- 
mals must all have been first assimilated 
by plants. 




60. The Sources of Plant Food. 

By observing plantlets of the bean or 

pumpkin a few days after germination, 

we may discover that the cotyledons, fig. 14. showing starch 

which were at first so plump, have shriv- cr y stals stored as reserve 

food in cell of potato. 

eled to a mere fraction of their former Highly magnified. 

size. This change is due to the fact that the food con- 

3 



±2 Principles of Plant Culture. 

tained by these parts has been absorbed by the develop- 
ing plantlet. The patrimony furnished by the seed is 
quicKly exhausted. Whence then comes the food that is to 
complete the development of the plant? Aside from the 
carbonic acid alread}' mentioned (59), several other sub- 
stances are required to build up the plant structure. These 
are almost wholly derived from the soil, through the medium 
of the water absorbed by the root-hairs (101). They must 
all be dissolved by the soil water or they cannot enter the 
plant, for they must pass through the cell-walls, which are 
not permeable to undissolved solid matter. 

61. The Elements regarded as Essential in the Food 

of Plants are carbon, hydrogen, oxygen, nitrogen, potassium. 
calcium, magnesium, phosphorus, iron, chlorin and sulfur. 
Some other elements that do not appear essential are also 
used by plants. All of these elements, except oxygen, are 
absorbed by the plant in the condition of chemical com- 
pounds, as water, carbonic acid and various nitrates, sul- 
fates, carbonates, etc. 

{VI, The Part Played by the Different Elements. 
Carbon is the chief constituent of vegetable substances and 
forms about half of their total dry weight. Plants obtain 
their carbon almost wholly from the air, in the form of car- 
bonic acid gas, which is a compound of carbon and oxygen. 
The leaves absorb and decompose this gas, retaining the 
carbon and giving off the oxygen. Hydrogen and oxygen 
arc obtained by the decomposition of water, which is a com- 
pound of hydrogen and oxygen. These enter into the con- 
struction of nearly all tissues. Nitrogen is one of the con- 
stituents of protoplasm (13). Most plants depend upon 
soluble nitrates in the soil for their nitrogen supply, but 



The Plant lei. 43 

those belonging to the natural order to which the clover 
belongs {Leguminosa (le-gu'-mi-no'-sae)) are able to appropri- 
ate nitrogen from the air (260). Phosphorus and sulfur 

assist in the formation of albuminous substances: potassium 
assists in assimilation (59); calcium and magnesium, while 
uniformly present, seem to be only incidentally useful. 
Iron is essential to the formation of chlorophyll (58). Ex- 
cept the carbon and, in the case of leguminous plants, a 
part of the nitrogen, all these substances are obtained from 
the soil through the medium of the water absorbed by the 
root- hairs (101). 

Of all the materials obtained by plants from the soil, but 
three, aside from water, viz., nitrogen, phosphorus and 
potassium (254) are needed in such quantities that the 
plants are likel} T to exhaust the supply, so long as water is 
not deficient. It thus appears that an adequate supply of 
water is the most important condition for the well-being of the 
plant, since it not only serves in nutrition, but is the vehicle 
b} r which all other food constituents, except carbon, are dis- 
tributed through the plant. The development of the plant, 
therefore, under natural conditions, depends ver} r much 
upon its available water supply. Comparatively few soils 
are so poor as to be incapable of producing good crops when 
sufficiently supplied with water. On the other hand, the 
richest soils are unproductive when inadequately supplied 
with water. Much of the benefit of heavy manuring un- 
doubtedly comes from the increased capacity it gives the 
soil for holding and transmitting water. 

63. Water is Necessary to Growth. The supplying 
of food material is not the only office performed by water 
in the plant. The unfolding and expansion of the plantlet 






44 Principles of Plant Culture. 

is largely due to a strong absorptive power for water posses- 
sed by the protoplasm within the cells. This force causes 
all living parts of plant? to be constantly saturated with 
water. More than this, it distends the elastic cell-walls 
with water until the} T are like minute inflated bladders. The 
pressure thus set up aids in unfolding the different parts 
from their snug resting place within the seed-case, and en- 
ables the plantlet to stand erect. Growth by cell division, 
it is true, begins rather early in the germination process, 
but this cannot take place unless the cells are first distended 
with water. A sufficient amount of water is absolutely 
necessary, therefore, to growth in plants. Foliage wilts in 
dry weather because the roots are unable to supply enough 
water to properl}' distend the cells, but growth is impossible 
in plants of which the foliage is wilted. When the water 
supply is abundant, on the other hand, and the absorptive 
power of the roots is stimulated by a warm soil (102), the 
pressure within the cells often becomes sufficient to force 
water from the edges and tips of leaves. The drops of 
water that so often sparkle on foliage in the sunlight of 
summer mornings, commonly mistaken for dew, are usually 
excreted from the leaves. In young plants of the caladium, 
water is sometimes ejected from the leaf -tips with consider- 
able force. 

The water of plants is almost wholly absorbed by the 
root-hairs (101), the leaves having no power to take up 
water, even in wet weather. The water of plants, with its 
dissolved constituents, is commonly called sap, except in 
fruits, where it is usually called juice. 

64. How Food Materials are Distributed through the 
plant. If we drop a verj' small lump of aniline blue into 



The Plantlet. 45 

a glass of clear water, we shall find that the lump will not 
retain its form and size, but infinitel} T small particles of it 
will become detached and move about to all parts of the 
water. This movement will not stop until the lump has 
entirety disappeared, and until eveiy part of the water con- 
tains exactly as much of the aniline blue as every other 
part. This equal distribution of the soluble material takes 
place in response to the law of diffusion, that tends to cause 
an}- soluble substance to become equally distributed through- 
out the liquid in which it is placed. The liquid, in the 
meantime, ma3 r remain quite stationary. The process would 
be the same if we were to put in a very small quantity each 
of several soluble substances at the same time. The move- 
ments of one of these substances would not interfere much 
with those of the others. 

Suppose the aniline blue in our glass of water had become 
equally distributed by diffusion. If we could remove some 
of it from the water in one part of the glass, it is clear that 
the particles of dissolved aniline blue would move from the 
other parts toward this point, and if this removal were con- 
tinuous, slow currents of the particles would move in this 
direction from all other parts of the glass. 

We may now understand how the materials from which 
the plant is built up are distributed to the different parts. 
The water absorbed by the root-hairs (101) is not chemically 
pure, but it holds in solution small quantities of various 
soluble matters contained by the soil, some of which are 
used by the plant during growth. As these useful matters 
are removed from the water of the cells, to be built up into 
food, the supply is replenished from the soil, not through 
any power of selection possessed b}- the plant, but in accord- 
ance with the law of diffusion. In like manner, the food 



f 



46 



Principles of Plant Culture. 



formed by assimilation (59) finds its way to the growing 
parts. Soluble matters not used by the plant are not taken 
in to the same extent because their equal distribution is less 
disturbed. 

The distribution of soluble matter in the plant is also 
promoted by transpiration (75). 

Section IV. The Inner Structure of the Plantlet 

Thus far, we have considered the plantlet mainl} T from 
the outride. But before going farther, it is well to learn 
something of its inner structure also. We have seen (12), 
that all parts of the plant are made up of cells, and that 
these cells differ in form and office in the different parts. 
The cells of the leaf, for example, are different in shape, and 
in the use they serve to the plant, from those of the stem, 
flower or fruit. 

65. The Epidermis 
(ep'-i-der'-mis). The plant 
is covered by a thin, translu- 
cent skin that extends over 
the entire surface of the 
leaves, stem and root, called 
the epidermis (Fig 15 Ep.). 
This skin is formed of rather 
thick-walled cells, and serves 
to protect the more delicate 
parts within. It may be 
readil}' withdrawn in some 
plants, as from the leaves of 
the liveforever,* and echev- 
eria,t and young stems of the plum. The exposed surface 

* Sedum telephium. t Cot yh don. 



Pal. 




Fig. 15. Showing section through 
leaf of Oldenburgh apple. Ep. epider- 
mis: Pal palisade cells; I. intercellular 
spaces. Highly magnified. See also 
Figs. 13 and 20. 



The Inner Structure of the Plantlet. 4.7 

of the epidermis of the leaves, fruit and young stems of 
many plants is transformed into a layer that is more or less 
impervious to water, called the cuticle (cu'-ti-cle). The ob- 
ject of the cuticle is to restrict evaporation (75). To still 
further protect the parts, a layer of wax is sometimes se- 
creted upon the outside of the cuticle, as in the fruit of 
man}' varieties of the plum and grape, where it is called 
bloom. 

Root-hairs (101) and the hairs and bristles on the stems 
and leaves of many plants are cells of the epidermis that 
are elongated outward. The epidermis must not be con- 
founded with the bark. It is replaced by bark in the older 
stems of woody perennial plants. 

To give further strength and firmness to the upper sur- 
face of the leaf, the first two or three tiers of cells beneath 
the epidermis on the upper side are usually placed endwise, 
(palisade cells) (Figs. 15, 13 and 3). The hardier varieties of 
apple, as the Oldenburgh (Duchess), have more numerous 
and more crowded palisade cells than less hard}* varieties. 
Compare the palisade cells of a leaf of the Oldenburgh apple 
(Fig. 15), with those of Fig. 3, which shows a section from a 
leaf of a tender variety of apple. 

66. Stomata (stom'-a-ta). Minute openings through 
the epidermis, connecting open spaces between the interior 
cells (intercellular spaces) with the external air, occur in the 
leaves and young stems of land plants. These openings 
are bounded by a pair of crescent-shaped guard-cells called 
stomata, (singular, stoma, (sto'-ma)) (Figs. 16 and 17 St). They 
are chiefly found on the lower side of leaves, and are ex- 
tremely numerous, but are too small lo be seen without the 
microscope. An average apple leaf has been computed to 



4 8 



Principles of Plant Culture. 



contain about 150,000 stomata to the square inch on its 
lower surface. 




Fig. 16. Showing stomata (st.) on leaf of the garden beet. Moderately mag- 
nified. (After Frank and Tscbirch). See also Figs. 13, 17 and 20. 

The guard-cells are delicately-balanced valves which are 
extremely sensitive to external influences. The}' are open 
.j n /, in strong light, but usu 



I 




ally closed in darkness 
and also when the 
leaves are wet. The 
water that escapes 
from leaves (75), and 
the carbonic acid that 
enters them (62) mostly 
pass through the sto- 



Fig. 17 Showing stomata (st.) on leaf of Olden- m ata. The slightly 



burgh apple. Highly magnified. raised Spots Or dots OU 

the smooth bark of the } T oung shoots of many woody plants, 
{lenticeh (len'-ti-cels)), serve a similar purpose to that of the 
stomata. 



The Inner Structure of the PlantJet. 



49 



67. The Growing Point. At the tip of the stem, and 
just behind the tip of the root, is a group of cells forming 
the so-called growing point. These cells divide very rapidly 
during the growing season, and from them, all other kinds 
of cells are evolved. 

68. The Vascular (vas'-cu-lar) Bundles.* While the 
plantlet remains within the seed-case, it mainry consists of 
cells more or less cubical or globular in outline. But 
scarcely does germination commence before some of the cells 
begin to increase greatly in length without a corresponding 
increase in thickness.f These elongated cells form in 

groups or bundles (vascular bundles) 
that extend lengthwise through the 
stem and roots, and since the individual 
cells overlap each other and are in inti- 
mate contact, the}' form threads or 
fibres. These fibres serve the double 
purpose of giving strength to the plant, 
and conducting water, with its dissolved 
food materials, to the different parts. 
By the absorption of the ends of some 
of the cells, tubes (ducts) of very con- 
siderable length are formed. In other 
cells of vascular bundles, the walls are 
fig is. Prosenchyma mu^ thickened and strengthened by 

cells from stem of rye. J 

Highly magnified. (After WOOdy deposits. These groups Or blind- 
Frank and Tschirch). ^ Qf ^^ ftnd ductg ^.^ ^ ^ 

divide, in the leaves, forming the so-called veins and vein- 




* Also called fibro-vascular bundles. 

f Cells of the former class are called Parenchyma (pa-ren'-chy-ma), and those 
of the latter class prosenchyma (pro-sen'-chy-ma). Fig. 18 shows prospncbyma 
cells from the stem of rye. Fig. 15 shows parenchyma cells from the apple leaf. 



50 Principles of Plant Culture. 

lets. In the roots, they divide in a similar manner, extend- 
ing lengthwise through all the branches and branchlets. 

Fig. 20 shows a cross section of a vascular handle of the 
sunflower. 




Fig. 19. Showing cross section of a vascular bundle of the common sunflower. 
(Heliauthns annnus). Highly magnified. After Prantl). See also Fig. 80. 

The threads in the stalk of Indian corn and the leaf stem 
of the plantain (Plantago) furnish examples of well-defined 

vascular bundles. In most stems, the vascular bundles are 
less clearly defined. In woody stems, they are closely 
crowded, which gives the wood its firm texture. In some 
woody plants, as the grape and the elder, a cylinder extending 
through the center of the stem is free from vascular bundles, 
forming the pitli. The young stems of asparagus, the ball 
of the kohlrabi and the roots of turnip become "stringy 
when the cells of their vascular bundles become thickened 
by the deposit of woody material in them. 

60. The Cambium (cam'-bi-um) Layer. In most 
plants having two or more cotyledons (46), a layer of cells 
that are in a state of division (15) exists between the bark 
and the wood, called the cambium or cambium layer (Fig. 20). 



- The Inner Structure of the Plantlct. 51 

It is in this layer that growth in diameter (71) of the stem 
occurs. The bark of plants having the cambium layer sep- 
arates readily from the wood, at times when growth is rapid, 
because the walls of the newly-formed cambium cells are 

Gu „ St 




e— - 



PTo. 20. Showing transverse section of corner of a bean stern Vjeia faba). 
C, cambium layer; <■., epidermis: Ctt, cuticle; ,S'', stoma. The dark, oval-shaped 
spots, extending both sides of the cambium layer are the. vas'-ular bundles; W, 
wood cells iff the vascular bundles. Moderately magnified. (After Pottel 

extremely thin and tender. The slimy surface of growing 
wood, whence the bark has just been removed, is due to the 
protoplasm from the ruptured cells. In plants having more 
than one cotyledon, the cambium line is usualh" readily dis- 
cerned in cross sections of the stem. — though it is rather 
more distinct, and the bark is more readily separable, in 
woody than in herbaceous" stems. In the latter, the part 



• Stems that do not have the hard, firm texture of wood, as of the potato, rhu- 
baro, etc., are said to be herbaceous. 



52 Principles of Plant Culture. 

within the cambium line corresponds to the wood of woody 
stems, and that without it corresponds to the bark. 

?0. Portions of Cambium from different plants may 
Unite b} T Growth. If a section of cambium from one part 
of a plant is closely applied to the cambium of another part 
of the same plant, or of another closely related plant, the 
two portions of cambium may unite by growth, a fact of 
great importance in horticulture since it renders grafting 
(383) possible. Plants having no cambium lawyer (71) can- 
not be grafted, because their stems have no layer of dividing 
cells — the only cells that unite by growth. 

71. How Stems Increase in Diameter. There is no 
cambium layer in plants having but one cotyledon (46), of 
which Indian corn, the grasses and the palms are examples. 
In such plants there is no clear separation between bark and 
wood. The stem enlarges for a time by growth throughout 
its whole diameter, after which it ceases to expand. 

In plants having two or more cotyledons, however, addi- 
tions to the bark cells are constantly being made, during the 
growing season, on the outside of the cambium layer, and 
additions to the wood cells, on the inside of it, (Fig. 20). It 
follows that growth of the bark takes place on its inner sur- 
face, and growth of the wood takes place on its outer sur- 
face. This explains the vertically-furrowed appearance of 
the bark of old trees, which is constant^ being split open, 
during the growing season, by the newly forming layer 
within. It also explains the ringed appearance of a cross 
section of a woody stem. A new ring of wood is formed 
each season on the outside of that previous^ formed, and 
the line separating the rings marks the point where growth 
in autumn ceased, and was renewed the following spring. 



, The Inner Structure of the Plantlet. 



53 



The age of a given part of the stem of a woody plant is ap- 
proximately indicated by the number of its wood rings.* 

72. The Vital Part of 
Woody Steins in plants hav- 
ing more than one cotyledon 

(46) is limited to a compara- 
tively thin la}-er of bark and 
wood, of which the cambium 
forms the center. The cells of 
the so-called heart-wood, and 
those of the dry and furrowed 
outer bark, have lost their pro- 
toplasm, and so are no longer 
alive, though the}' serve a use- 
ful purpose in adding strength 
and protection to the vital layer. 
The heart-wood of a tree may 
largely deca} T without material- 
ly interfering with the vital pro- 
cesses. (Fig. 21). 

73. The Healing of 
Wounds. Cambium cells ex- 
posed to the air, by partial or 
complete removal of the bark, 
soon perish, hence growth 

., Fig. 21. Live poplar tree with hoi- 

ceases in a part of the stem low trunk showing t0 what extent 

thus injured. The Uninjured the heart-wood of a tree may decay 

without destroying its life. Madison, 

cambium cells on the borders of >yi S . 




* More than one wood ring is sometimes formed in a season. If growth ceases 
during the summer from severe drought, or other cause, and is renewed later the 
same season, an extra ring is formed. 



54 



Principles of Plant Culture. 



the wound may, however, by division (15), form a cushion of 
new material that gradually extends itself over the injured 
part. A new cambium layer may thus be formed over the 
wound if it be not too large, so that growth of the stem 
may be resumed at this part. The same process occurs 
when a branch is cut off near its union with the stem. The 
wound, if not too large, is "healed" by new growth from 
the adjacent, uninjured cambium cells. (Fig. 22). In 





Fig. 22. Healing of wound 
formed by cutting off a branch 
.(A). 



Fig. 23. Showing callus 
at 1'ase of willow cutting. 



planted cuttings, the uninjured cambium cells at the base, 
by continued division, form the callus (cal'-lus). (Fig. 23.) 
Exposure of the bark to undue heat or cold may destroy 
the cambium, causing sunscald (186). 



The Water of Plants and Its Movements. 55 

Section V. The Water of Plants and Its Movements 

74. Plants Contain Large Amounts of Water. We 

have seen (63) that the cell-walls of living plants are con- 
stant^ saturated with water, and that the cells of the grow- 
ing parts are always more or less distended with it. The 
proportion of water contained in living plants is generally 
very large. In the root of the turnip, and in some fruits, it 
maj T exceed ninet} T per cent, of the whole weight. It is 
greatest in young plants, and in the younger and growing 
parts of older plants. The proportion of water is not con- 
stant in the same plants, but varies within certain limits, 
with the water content of the soil, and with meteorological 
conditions. 

75. Transpiration (trans-pi-ra'-tion). The water passes 
off more or less rapidly from parts of plants exposed to the 
air, — usually as an invisible vapor. This invisible escape 
of water from plants is called transpiration. It is mainly 
due to evaporation of water from the plant into the air, the 
same as takes place from other moist material. But fluctu- 
ations occur in the amount of transpiration from living plants 
that do not occur in dead organic material under similar 
conditions. For example, transpiration is more rapid in 
light than in darkness, because the stomata (66) are open 
in the light and thus facilitate the escape of water from the 
intercellular spaces. Plants poorlj T supplied with nourish- 
ment transpire more freely under the same conditions than 
those well supplied. The amount of transpiration varies 
greatly in different plants, and depends upon the leaf sur- 
face, the nature of the epidermis and cuticle (65), the num- 
ber of stomata (66), etc. Some plants,- as purslane, the 



56 



Principles of Plant Culture. 



sedums, cacti etc., have special water-storing tissue, from 
which transpiration is extremely slow. 

Experiments indicate that the transpiration from most 
leaves is between one-third and one-sixth as much as the 
evaporation from an equal area of water. W'hen we take 
into account the immense leaf surface of a large tree, it is 
evident that the aggregate transpiration must be very great, 
as is often illustrated by the dwarfing influence of trees 
upon adjacent crops in dry weather. (Fig. 24). Transpira- 
tion is much more rapid during dry than during wet weather, 
and in the rare atmosphere of high altitudes than in the 
denser atmosphere of low lands. 

Excessive transpiration, as occurs in very dry weather, is 
detrimental to plants, since it reduces the water pressure 
within the cells below the point where healthful growth can 
take place (63); but normal transpiration, i. e., in amount 
not sufficient to interfere with healthful growth, is doubt- 
less beneficial, since it aids in carrying food materials from 
the soil into the leaves, where they are needed for assimila- 
tion (59). For this reason, plants native to regions having 
a rather dry atmosphere, do not thrive in greenhouses unless 
abundant ventilation is given to encourage transpiration. 




Fio. 24. Showing how a spruce hedge dwarfs an adjacent corn crop in dry 
weather. Madison, Wis. 



The Water of Plants and Its Movements. 57 

76. Trees are Detrimental to Crops in their vicinity 
not onty by the shade the} 7 cause, but by their exhausting 
effect upon the soil moisture in dry weather. The distance 
affected b} 7 a group of trees is often much greater than is 
supposed. The accompan} 7 ing illustration (Fig. 24) shows 
how an evergreen hedge may restrict the growth of corn in 
an adjoining field. We should not infer from this, however, 
that trees are generally detrimental to agriculture. Thev 
serve many useful purposes. 

Experimental crop3 intended to be comparable with each 
other should not be planted near growing trees. 

77. The Brittleness of Plant Tissues depends upon 
the degree of water pressure within the cells. Foliage is 
usually most brittle during the morning, and least brittle 
during the latter part of the day, because transpiration is 
most active during the warmer hours of the da} 7 . Lettuce 
and other salad plants are, therefore, apt to be most crisp 
and tender when cut in the morning. Tobacco, on the other 
hand, in which breaking of the leaves is detrimental, is pre- 
ferably cut in the afternoon. Young hoed crops are gener- 
all} 7 less injured by the smoothing harrow in the afternoon 
than in the morning, and grass intended for hay usually 
dries soonest when cut in the afternoon. Lawn grass gen- 
erall} 7 cuts easier in the morning than in the afternoon. 

Slightly withered vegetables ma} 7 have their crispness 
partially restored by soaking in water for a time. 

78. The Evaporation Current. Since the water of 

plants is taken in from the soil through the root-hairs (101), 

and escapes more or less rapidly by transpiration (75), it is 

clear that, in leafy plants, a current of water must pass from 

the roots through the stem and branches into the leaves, and 
4 



58 Principles of Plant Culture. 

that the rate of this current will depend much upon the 
rate of transpiration from the foliage. When the soil moist- 
ure is reduced, and evaporation is excessive, this upward 
current of water is not always sufficient to maintain the nor- 
mal pressure within the cells (63), hence the foliage wilts, or 
the leaves roll up, as in Indian corn and some other plants 
of the grass famil} T . This current passes chiefly through the 
younger vascular bundles (68), which, in trees, constitute 
the so-called sap-wood, since the cells of these are less ob- 
structed by woody deposits than those of other tissues. 

The physical forces that cause the soil water to rise to 
the tops of the tallest trees are very imperfectly understood, 
but the pull produced by the evaportion of water from the 
leaves and osmosis* play important parts. 

79. The Flow of Sap in Spring. In the temperate 
zones, evaporation from the leafless stems of deciduous 
trees and shrubs nearly ceases during winter. The 
portion of the roots of these plants, however, that lies 
below the frost line, continues to absorb water, which gradu- 
ally accumulates in the stems and branches. On the return 
of spring weather, the rise in temperature causes expansion 
of the tissues of the stem as well as of the air and water 
within it. This creates so much pressure in some trees and 
shrubs that water flows freely from wounds in the wood r 
bearing with it, of course, the materials it holds in solution. 
This happens when we tap a sugar maple tree in spring. 
Alternate rise and fall of temperature increases the flow of 
sap, because with each contraction, new supplies of water 

* Osmosis is the tendency that causes two liquids of different densities, when 
separated by a permeable membrane, to mix with each other. The less dense 
liquid tends to flow into the more dense one with a force corresponding to the dif- 
ference in their densities. Cell contents are usually denser than soil water, hence 
the latter tends to flow into the cells, and thus to rise in the p'ant. 



The Water of Plants and Its Movements. 59 

or air are drawn into the stem, and thus the pressure is 
maintained. 

The popular idea, that the flow of sap in spring is due to 
a rapid rise of water through the stem at that season, is er- 
roneous. The sap is really rising through the stem much 
faster in midsummer than in early spring. Sap ceases to 
flow on the opening of the buds, because transpiration (75) 
from the foliage quickly relieves the abnormal pressure. 

80. The Current of Assimilated Food. The food of 
the protoplasm in the different parts of the plant is assimi- 
lated almost wholly in the leaves (121). But we know that 
growth occurs, not only in the leaves, but in the stem and 
roots as well. It is clear, therefore, that when the stem and 
roots are growing, a movement of food matter must occur 
from the leaves into these organs. This movement maj- be 
demonstrated by a simple experiment. If a notch is cut 
into the stem of any of our common woody plants during 
spring or summer, deep enough to pass through the bark 
and a little into the wood, a callus, or cushion of new cells 
(73), will soon form on the upper side of the notch, but not 
on the lower, showing that the material from which new 
cells are formed is passing downward. Close examination 
will show that this callus forms just outside the union of the 
bark and wood. In all plants having more than one coty- 
ledon (46), this current is through the inner layers of the 
bark. The assimilated matter is dissolved in the water that 
saturates the cell-walls, and passes from the leaves to other 
parts of the plant by diffusion (64). 

81. Killing Trees by Girdling. To destroy the life 
of a tree that can not be conveniently removed, we ' : girdle" 
it by cutting a notch about the trunk beneath the lowest 



60 Principles of Plant Culture. 

branch. This outs off the downward current of assimilated 
food, and so starves the protoplasm of the roots. If the 
notch is made after the leaves have expanded in spring, 
and extends only through the bark, the leaves may remain 
fresh for several weeks, since the transpiration current, 
which passes through the sap-wood (78), may continue. 
The roots, however, since they receive no nourishment, will 
soon cease to grow and will die from starvation before the 
following spring. If the notch is cut deep enough to reach 
through the sap-wood, cutting off both the ascending and 
descending currents, death of the tree speedily ensues. 

82. Root Starvation may occur Without Girdling. 

In seasons of extreme drought, when the leaves are poorly 
supplied with crude food materials from the soil, the amount 
of assimilated material ma} T be so meagre that the food cur- 
rent will be exhausted before it reaches the roots. In such 
cases the roots perish, and the tree is found dead the follow- 
ing spring. This most frequently occurs with trees on poor 
soil, that have suffered from insect attacks, as well as from 
a dearth of water. It often occurs also in recently trans- 
planted trees that fail to make satisfactoiy growth the first 
season. 

83. To Destroy the most Persistent Weeds we 
Starve the Roots by preventing all leaf growth (339). 

84. Restriction of the Growth Current Promotes 

Fruitfulness by causing an accumulation of assimilated 
food in the stem and branches (135 B). 

S5. The Storage of Reserve Food. In healthy plants, 
food is assimilated faster than it is consumed by growth. 
The surplus is used in the production of flowers and seeds 
(135 A), and in repairing damages, as the healing of wounds 



The Water of PIa?its and Its Movements. 61 

(73), or the replacement of leaves destroyed by insects or 
otherwise. Perennial plants depend upon their reserve 
food to nourish their protoplasm during the dormant period, 
when their leaves are wanting or inactive, and to supply 
themselves with new foliage and root-hairs in early spring. 
The reserve food in dormant cuttings (358) enables them to 
form roots and expand their buds. 

The surplus food of plants may be in the form of starch, 
as in the potato (Fig. 11), wheat and sago; sugar, as in the 
sugar cane, sugar maple and beet; or oil, as in cotton seed, 
flax seed and rape. Aside from the seeds, which are always 
stocked with reserve food, certain plants living more than 
one } T ear, as the potato, beet, onion, kohl-rabi etc., have 
special accumulations of food in certain parts, and the parts 
of plants that contain such reserve food are most valuable 
as food for man or animals. In wood} 7 plants, the surplus 
food is more evenly distributed through the different parts, 
though the older leaf-bearing wood is usually best supplied. 

86. How Plants Use their Reserve Food. Annual 
plants (337) expend all their reserve food in the production 
of ver} T numerous flowers and seeds and then perish as soon 
as the seed is ripe. Biennial plants devote the first season 
of their life to storing an abundant food suppl}*, which is 
expended in flower and seed production the second year. 
Our seed crops, as oats, corn, peas and beans, are mostl} 7- 
annuals; our vegetables other than seeds, as beets, cabbage, 
parsnips and celery are mostly biennials. Perennial plants, 
in normal condition, expend onl} 7 a part of their reserve 
food, in any one season, for the production of flowers and 
seeds, withholding the remainder for nourishment through 
the winter and to develop leaves the following spring. 



62 Principles of Plant Culture. 

Section VII. The Root and the Soil 

With the out-door cultivator, the part of the plant envi- 
ronment that lies beneath the soil surface is more under 
control than the part that lies above it. He can do little to 
change the composition or temperature of the air, or the 
amount of sunlight; — he ma}' do much to influence the 
fertility, the texture, the drainage and the aeration of the 
soil. A knowledge of the roots of plants, and of the soil in 
in which the} 7 grow and feed is, therefore, of the utmost 
practical importance. 

S7. The Root's Office. The roots of land plants serve, 
1st, — to anchor the plant in the soil, enabling the stem or 
stems of erect species to grow upright, and, 2d, — to supply 
the plant with water with its dissolved food materials (63). 

88. The Root Originates in the Stem. As we have 
seen (41), the primary root develops from the lower or 
" root-end " of the hypocotyl. But lateral roots may develop 
freel} T from other parts of the stem. If we examine the 
base of the stem of a plant of Indian corn, a few weeks after 
planting, we may see that the main roots start out above the 
point at which the stem was originally attached to the seed; 
and if we pull up a pumpkin vine or an untrellised tomato 
plant, late in summer, we often find it rooted from the stem 
at some distance from the original root. Lateral roots 
originate in the internal tissues of the stem or root, and not 
upon the surface as do buds (132). 

89. Moisture Excites Root Growth. Roots develop, 
as a rule, from portions of the stem that are maintained for 
a certain time in contact with abundant moisture. In the 



The Root and the Soil. 63 

pumpkin vine and tomato plant above mentioned, proximity 
to the soil furnishes a moist atmosphere. A corn-stalk 
pegged down to the ground for some distance will usualty 
root at all the joints of the stem in contact with the soil. A 
potato plant grown under a bell glass, where the air is nearly 
saturated, will put out roots at any joint of the stem. In 
parts of the tropics where the air is very moist, certain 
plants, as orchids and the Bairyan tree {Ftcus Indica), emit 
roots freely from the stem above ground. Cuttings (358) 
and la3 T ers (349) form roots because they are maintained in 
contact with abundant moisture and at a suitable tempera- 
ture. Cuttings of some plants, as the willow and nasturtium 
(Tropceolum), root promptly when their stems are immersed 
in water. 

90. Oxygen is Necessary to the Life of Roots. Since 
the cells of newly-formed roots are filled with protoplasm, 
the} T must have access to the oxygen of the air, or they can 
neither grow nor live. This is shown by a simple experi- 
ment. Boil a quantity of water fifteen minutes, or longer, 
to exhaust it of free oxygen, and then cool it quickly by 
setting it in cold water. Now place a healttry slip of some 
plant that roots freely in water, as willow, nasturtium or 
wandering jew (Tradescantia), in each of two tumblers. 
Pour part of the cool, boiled water into one of the tumblers 
and add a little olive oil to form a film over the liquid and 
prevent its absorbing more air. Then agitate the rest of 
the water vigorously, to impregnate it again with oxygen, 
and pour some of this into the second tumbler. Set both 
tumblers in a light, warm place. In a few da} T s, roots will 
start freely from the slip in the tumbler in which the water 
has access to the air, but not in the other (Fig. 25.) If now 






1 



\\ w >ther oil inhered water that has 

Ivon o\hansu\l of ItS ow-'vn l\\ boiling, the root R I S00H 
fife 

The copious forma 

tion »M* root hairs vli'H 
that reach OUt into the 

uumsi atmosphere of 
the seed tester 

ami that so Often till 

the soil oa> ities with a 
delicate, cottony don a, 
is further proof that 
roots seai oh for air as 
well as water Phe to 
tal absence of live 
rootlets in the puddled 
Is of badlj tilled 

a, shows that i. 

w ill not penetrate soil 

toon which the air has 

lai .... x -o t ;vm n.u been expelled bv undue 

on while wet Plants in over watered greeuhouse 

pots sometimes send rootlets into the air above the soil to 

secure the oxygen from which their roots have been de 

prived 

\)\. iho Uieal Soil for i ami Plants must contain 

enough plant food and water to toll) SUppl\ the plants, ami 

\ot be so porous that air can circulate through it. and oome 
in contact with the roots Baoh particle of suoh • soil is 
surrounded with a thin (tin of water, while between the p 
tides are spaces connected with each other, and filled with 




'/ t Root and t/u Soil. 

mo 

Tbe root bail i (10 
tbe 

into cavities filled ivith 

draw in the nrell i >od 

on 
75), am 

92* The Soil Scene Ol Constant Change 

part of the soil in which the root Dm 

tj'l changi m. On the e it 

If l:. 

T1j<- dead remain* of plant* and an on- 

tain are undergoing deeoi on dm 

ground of i - of 

- . 
acid, irhtcb tuppl higher 

able food element— nitrogen [255) if for:/, 
carbonic acid I i from tbe air during . 

-r<;<: to -lowly Hi- be mini 

rendering avails 

plant, food. Ifj printer, tbe fro* ><- compact 

particles of clods, making tbe latter perm air and 

rootlet* or flake* ofl new fragment* oi tbn* uii . - 

inpplie* of mineral fertil 

93* The Importance of Organic Matter in tbe Soil. 

Crop* secure a large part, of tbeir nitrogen ther 

food material! . dead organic matter, i, e., animal or 

getable material*. The application of ench nib tbe 

-.oil is, therefore, of great importance, where large 

ected. Stable an<l bam yard manur< oflal from 

tanneries, bren J iralnable 



66 Principles of Plant Culture. 

for this purpose, when wisely used. Not only does organic 
matter in the soil furnish plant food, but while in a partially 
decomposed state (humus), it renders the soil porous and 
greatly increases its water-holding power. 

94. The Soil Needs Ventilation. The roots of grow- 
ing plants, and the decomposition of organic matter in the 
soil, tend constantly to exhaust the soil of its free oxygen, 
and to replace this with carbonic acid, which is not used by 
roots. Hence, without some interchange between the con- 
tents of the soil cavities and the atmosphere above, the roots 
sooner or later become smothered and perish. In sufficiently 
porous soil, changes in temperature and atmospheric pres- 
sure, aided b\ T wind and rain, furnish the needed soil venti- 
lation, but in poorly drained soils, and soils not thoroughly 
tilled, the roots of plants often suffer from insufficient oxy- 
gen. A puddled crust on the surface of cla} T ey soil, due to 
the compacting influence of rain, is a great hindrance to soil 
ventilation. 

95. Hotbeds (3C>5) Require Especial Care in Venti= 

lation, since they usualh* contain large quantities of decom- 
posing organic matter (manure), which rapidly absorbs oxy- 
gen from the soil, replacing it with carbonic acid. 

96. Drainage Promotes Soil Aeration by forming an 
outlet for the surplus water that would otherwise fill the 
cavities. Although moisture is essential to root giowth, 
land plants do not prosper with their roots immersed in 
water. True, most plants may be grown in ' ; water culture,'' 
i. e., with their roots, from germination, grown in water that 
is freely exposed to the air; but the roots of land plants 
soon smother for want of free oxygen, when the soil cavities 



The Root and the Soil. 67 

are filled with water, because the soil tends to prevent the 
water within its cavities from absorbing air. 

97 . Potted Plants should have Abundant Provision 
for Drainage, and the outside of the pots should be kept 
clean, to admit air through their walls. Potting soil should 
contain sufficient sand and humus (93) so that it does not 
readily become puddled by watering. 

98. Potted Plants should be Watered with Care. 
They should receive sufficient water so that the soil particles 
are constantly surrounded with a film of water, but not so 
much that the soil cavities remain filled. 

91). How the Root=Tip Penetrates the Soil. Darwin 
made the interesting discovery that the root-tip, in advanc- 
ing through the soil, does not move in a straight line, but 
has an oscillating motion, which enables it to take advan- 
tage of openings between the soil particles. The force with 
which the root-tip is pushed forward, b} T increase in length 
of the root, was calculated by Darwin to be at least a 
quarter of a pound, in some cases, while the increase of the 
root in diameter may exert a much greater force. The 
root-tip is protected in its passage through the soil by a 
thimble-like covering called the root-cap* 

100. Growth of Roots in Length. Since the soil 
offers more or less resistance to the growth of roots, in land 
plants, it is evident that the roots could not elongate 
throughout their whole length at once. On the contrary, 
the part that increases in length is limited to a short por- 
tion just behind the root-tip. Sachs found that the part of 
the rootlet of the broad-bean, that increased in length by 



* The root-cap is readily seen without a magnifying glass when a beau plant is 
grown in water. 



68 



Principles of Plant Culture 



growth, scarcely ox- 
ceeded half an inch 
ong. In Fig. 26, the 
parts that are increas- 
ing in lengtb are con- 
siderably shorter than 
the root tips. \\\. T.) to 
which no sand adheres. 

101. The Root= 
Hairs (Fig. 27 B.) de- 
velop just behind the 
elongating part o\' the 
rootlet, ami are present 
in nearly all plants. 
Their object is to ab- 
sorb water, with the 
food materials it con- 
tains. The root-hairs 
greatly increase the ab- 
sorbing surface o\ the 
roots, just as leaves in- 
crease the absorbing 
& "^surface of the plant 
above ground, Each 
root-hair consists of a 
— ^-r-sinulo elongated cell 
(Fig. 28), and in com- 
mon with the cells in 
other living parts of 

", u . , , T , , the plant, is rilled with 
Fig. 26. Root3 of young wheat plant. The parts ^ ' 

inclosed in sand (B 11 ) are surrounded by root- protoplasm (13). As 

hairs. K. T. root-tips: e. older parts of root. Na- , . .. 

turalsize. (After Frank and Tschirch) tlie extremity OI tlie 




The Jtoot and the Soil. 



69 



root advances through the soil by growth, new root-hairs 
arc formed in front of the older ones, while those fart); 

hack as rapidly die off, so that only a short 
portion of a rootlet bears root-hairs at an}' 
one time. In Fig. 2.">, root-hairs are visible in 
the left, glass, and in Fig. 5, they may be teen 
OH the hypocotyl of some of the germinating 
corn grains. \\\ Fig. 27 A. and in Fig. 20, the 
parts of the root bearing root-hairs are indi- 
cated by the sand which adheres to th- 
parts. It is usually difficult to see root-hairs 
of plants growing in the natural soil, but they 
may sometimes be discovered, with the help 
of a pocket magnifying glass, by carefully 
removing the soil particles about the younger 

*'"'• "' ~"" A ~ roots, when their silkv network maybe seen 
lingt of turnip, • ^ 

•howl ng root- filling the smaller pores of the soil, or envelop- 

b ai rg. (A f t h r . ., ., ,. , ... no , 

,. . . ing the soil partieles. I- lg. 28 shows a mag- 

Trebirch). nified root-hair of the wheat plant, closely 





J/'.. -'-. Magnified rooUhair of wheat, in contact with .-.oil partie'ea (After 

Sa< -lis;. 

attached to some particles of soil. The root-hairs are able 
to take up water freely, even from soil that does not appear 
ver} r wet, because each soil particle is enveloped in a thin 
layer of water (91). .Still more interesting is the fact, that 
root-hairs are able to dissolve mineral matters in the soil, 
by means of excretions, most important of which is carbonic 
acid, thus permitting the plant to use these matters as food. 



70 Principles of 'Plant Culture. 

10*2. Root-Hairs Absorb Water with considerable 
Force. It is the absorptive power ol' the root -hairs that 
causes water (sap) to How so freely from injured stems ol' 
grape vines* and some other plants in spring, and from 
wounds in the trunks ol' some trees in summer. This force 
is probably due to the absorptive power ol' the protoplasm 
in the very active young root cells. It is affected by the 
temperature of the soil, within eertain limits, lessening as 
the temperature falls, ami increasing as it rises. Saehs 
found that the foliage oH plants ol' tobacco and pumpkin 
drooped when the temperature ol' the soil in which they 
were growing was reduced much below 55° E\. showing that 
the roots, at that temperature, did not absorb sufficient 
water to compensate for the loss by transpiration (75), 
When the soil is warm, on the other hand, the absorptive 
power Of roots may be sufficient to force water from the tips 
of leaves during eool nights when transpiration is slight (63), 

103. Only the Youngest Parts of Roots are Active 
in Absorption. The part from which the root-hairs have 
perished absorbs little water, but is chiefly useful in gi\*ing 
strength and in conducting the plant tluids. 

The absorbing part of any given rootlet is. therefore, com- 
paratively short. It follows that the amount ol' nourish- 
ment a given plant can receive will depend upon the number 
of its root -tips. Our treatment of the plant should, there- 
fore, be aimed at promoting the formation ol root-tips. In 
other words, we should encourage root branch ing.f How may 
we do this; 



llales found the absorbing force of the roots o( a grape vine equal to the 
weight o( a column of niereury thirty-two and one-half inehes high. 

| Boot branches must not be confounded with root-hairs, in Fig. 26j branches 
of the roots appear at e. e. e. The branches bear root-hairs when of suttleient 
length, but root-hairs never develop into branches. 



The Root and the Soil. 



7i 



KM. The Branching of Roots, in Land plants, appears 
to depend much upon the amount of tree oxygen (31) and 
available plant food the soil contains, so long as the moist- 
are supply is sufficient In cultivated grounds, the roots 

of crops usually branch most freely just at the bottom of 
the layer of soil stirred by tin; plow, this being the point at 
which the supply of oxygen, plant food ami moisture are 
probably best suited to root growth. As the depth of till- 
age is increased, roots branch freely at a greater depth. 
Masses of decomposed manure, beneath the surface of the 
soil, arc usually penetrated through and through with finely 
branched roots; and fragments of hone in the soil are often 
inclosed in a mat of delicate rootlets, These materials fur- 
nish plant food in abundance. Roots that penetrate the 
deeper and more compact layers of soil, on the other hand, 
and those in poor and dry soils, are comparatively little 
branched. It is clear, therefore, that unless a soil is well 
aerated (94) by a proper system of tillage, and by draining 
if need be, and unless it contains abundant soluble plant 

food in the aerated part, the roots 
of plants growing upon it will not 
branch freely .and hence the plants 
cannot be well nourished. 

105. Transplanting M 0) 
and Root Pruning (416) Stimu = 
late Root Branching. Removing 

the terminal growing points of 

either the stem or root stimulates 

the development of other growing 

]j. 29. snowing how root points farther back. Transplanting 
pruning stimulate! root branch- . ,. , , . 

lng or root pruning accomplishes this 




/- 



Principles of Plant Culture. 



end, in the case of roots (Fig. 2D). While these operations 
probablj' do not often increase the total number of root- tips, 
and hence do not enable the plant to take up a greater 
amount of nourishment, the}' do cause a more compact root 
system, which is of very great advantage in young plants 
grown in the seed-bed or nursery, for subsequent removal to 
a less favored environment. 




Fig. 30. Showing effects of transplanting on root growth of celery plants. 
The left two plants were transplanted when quite small; the right two were not. 
(After Green). 



The Root and the Soil. 73 

106. Pricking Off Young Seedlings, i. e., transplant- 
ing them from their seed-box into other boxes or beds, is a 
most important preparation for their final transplanting. 
They should receive as good care after pricking off as before, 
with which, having increased room and light, the} T soon 
develop many new rootlets near the base of the stem, which 
need be little injured in the final removal. 

107. Nursery Trees are Greatly Benefited by Trans= 
planting them once or twice before the final planting out, 
for the reasons named in the last paragraph. 

108. Root Pruning (416) may sometimes be employed 
as a substitute for transplanting, and is especially useful in 
the case of trees that form few branch roots, as the hickory 
3,nd walnut. 

109. The Horizontal Extent of Roots is probably 
much greater than is generall} 7 supposed. In upright-grow- 
ing plants, the area occupied by the roots usually exceeds 
that covered by the foliage, while in spreading and trailing 
plants, the roots are probably rarely less in extent than the 
branches. It appears from the observations recorded that, 
even in such plants as the melon and squash, the horizontal 
extent of the roots usually equals or exceeds that of the 
runners. As the diffusion of soluble matters in the soil 
water is probably much hindered by the friction of the soil 
particles, the roots of plants need to travel farther after 
food than do the branches, which develop in a freely circu- 
lating medium. Especially is this true of plants growing 
in poor soil. 

110. The Depth of Roots in the Soil. It appears 

from the observations recorded that the extreme depth 
5 



74 Principles of Plant Culture. 

reached by roots is generally loss than their greatest hori- 
zontal extent The distance reached by the deeper roots is 
probably governed much by the nature of the subsoil and 
the depth of free ground water. But in most crops on cul- 
tivated ground, a comparatively small part of the roots de- 
velop below the plow line. At the Geneva Experiment 
Station" the chief root -feeding ground of the field and garden 
crops grown in that locality appeared to be from three to 
ten inches below the surface, while that of crops that make 
very large development of stem and foliage during summer, 
as Indian corn, sorghum, tobacco and the Cucurbitse (42), 
appeared to be shallower than in slower growing crops. 

A portion o( the roots of many crops grow very near the 
surface ol' the ground. Branches from the main horizontal 
roots often grow upward as well as in other directions. At 
the Geneva Experiment Station, numerous roots of sweet 
corn were found within an inch of the surface, and in a tall- 
growing southern corn, roots of considerable size started 
out at a depth of only half an inch. The main root of a 
Hubbard squash vine was traced a distance o\' ten feet, in 
which its depth varied from two to five inches. In tobacco 
fields, the rootlets sometimes literally protrude from the sur- 
face of the soil, in warm, wet weather. 

111. The Rate of Root Growth, in rapidly developing 
plants, is often extremely fast. President Clark, formerly 
of the Massachusetts Agricultural College, concluded from 
very careful examinations and measurements of the roots of 
a squash vine grown under glass, that during the latter part 
of the growth period, rootlets must have been produced at 
the rate of at least one thousand feet per day. 



■ See Eteporl of Now York Agricultural Experiment Station, 1836, p. 165. 



The Stern. 



75 



1 12. Relation of Roots to Food Supply. Hoot growth 
is relatively less, in the extent of ground occupied, in moist 
and fertile soils, than in poorer and drier soils, but the roots 
are proportionally more branched. In wet seasons, a given 
plant has less extensive root development than in drier sea- 
sons, because the roots may secure the needed food and 
water from a smaller area. Nursery trees grown on fertile 
soils have a more compact root system than those grown on 
poorer soils. 

1 13. Root Tubercles. 
Plants belonging to the 
pulse family (natural or- 
der Leguminosae (le-gu- 
mi-no'-sae)), of which the 
clover, pea and bean are 
familiar examples, when 
grown in ordinary soil, 
have swellings or tuber- 
cles on their roots (Fig. 
31). These are caused by 
parasitic fungi known as 
bacteroids (bac'-te-roids) 
and are of special interest, 
because the bacteroids 
producing them render 
nitrogen of theair, which 
plants have no power to 
directly appropriate, available as plant food (260). 

Section VIII. The Stem 

114. As the root develops from the base of the hypo- 
cotyl, the plumule, or primary shoot (56), develops from the 




I i'.. 31. Young clover plant showing tu- 
bercles (t) on roots. (From nature). 



;<• 



Principles of Plant Culture. 



U.St 



other end, and becomes, at least for a time, the main axis 

or stem of the plant. 

1 1 5. The Stem 
is, generally speaking 
the part of the plant 
that supports the 
leaves. In exceptional 
cases, as in the potato 
(Fig. 32) and quack 
grass, a part of the 
stem grows beneath the 
ground (underground 
stems), when the leaves 
usually do not develop; 
and in a few plants, as 
in some cacti, the stem 
performs the whole of- 
fice of leaves. The stem 

Fio.32. Potato plant. U.st., underground stems, may be Strong CllOUgh 
R. Roots. The tubers are the thickened distal . ., 

ends (116) of the underground stems. Much re- t0 su PP ort lts own 

duced. (After Frank and Tschirch). weight, as in trees and 

shrubs, or it may depend upon other objects for its support 
as in vinos. 

110. Nodes and Internodes. Unlike -the root, the stem 
is developed in successive sections, comparable in part to 
the stories of a building. Each section or stor} 7 consists of 
one or more leaves, attached to the distal* end of a portion 
of the stem. The part of the stem to which the leaf or 
leaves is attached is called a node and the part below the 




* Distal means farthest from the point of origin, i. e., the point at which growth 
started. It is opposed to proximal, which means nearest the point of origin. 



The Stem. 



11 



N-— 



?---fj 



node, or in the stem as a whole, the part between the nodes, 
is called an internode. 

The nodes are distinctly marked 
in the younger stems of most 
plants by a slight enlargement, or 
by leaf-scars, if the leaves have 
fallen (Fig. 33). The nodes are 
centers of vital activity, and are 
the points at which lateral grow- 
ing points (buds. (128)) are nor- 
mally formed, and whence roots 
usually start first in cuttings and 
layers (358, 349). 

1 1 7. The Stem Lengthens 
by the Elongation of the Inter= 

nodes, as well as by the formation 
of new ones. As the internodes 
soon attain their ultimate length, 
it follows that the stem lengthens 
onl}' near its distal end. An inter- 
node that has once ceased elongating does not afterward 
resume it. hence the internodes of perennial plants that are 
only partiall}' elongated at the close; of the growing season 
remain undeveloped. When growth is resumed in spring, 
the formation of a comparatively long internode beyond the 
very short ones of autumn usually forms a perceptible ring 
about the shoot, which enables us to readily locate the point 
at which growth started in spring (Fig. 34). and we can often 
determine the amount of growth that took place during the 
preceding season or even farther back. 



Fig. 33. Noden(N) A, of the 
box elder, Negundo aeeroide, B, 

of the wild grapf. Wis riparta. 



7 8 



Principles of Plant Culture. 



118. The Ultimate Length of the Internodes in any 

plant, or any part of a plant, depends upon the rate of 
growth, — rapid growth producing long inter- 
nodes, and vice versa. In the same species, 
therefore, the average length of the internodes 
is much greater in vigorous, young plants than 
in old ones, in the main, central shoot than in 
the branches, and when growth is well started 
in spring than during its decline in autumn. 
The diameter of the young internodes is gener- 
ally in proportion to their length, hence rapidly- 
growing shoots are usually thicker than slower- 
growing ones. We can judge of the compara- 
tive vigor of nursery trees by observing the 
length and diameter of the internodes. 



\i** 



F I G. 34. 
Union of 
new and 
older wood. 



119. The Stem Elongates Fastest just 
behind the growing point (67), and at least in 
young plants, just behind the primary or original growing 
point (56). When we desire to check growth of the stem, 
therefore, we remove the terminal growing point by " 'pinch- 
ing " (416). 

120. Pinching Stimulates Branching because remov- 
ing the terminal growing point stimulates the development 
of other growing points farther back (105). 

Section ix. The Leaves 

We have seen (116), that one or more leaves are normally 
formed at each node of the stem. 

121. The Function of Leaves is Assimilation (59). 

Since assimilation takes place onl} T in light, the cells of 



The Leaves. 79 

leaves are, in most plants, so arranged as to best expose 
them to light, i. e., in thin, more or less horizontal plates, 
which are strengthened, and at the same time supplied with 
water, by a network of vascular bundles (68) connecting 
with the stem. They are protected by the epidermis (62), 
but have access to air through the stomata (66). 

Each leaf, like the stem and root, is developed from one 
or more growing points (67), one of which forms the ter- 
minus of each lobe or division of the leaf. Cell division in 
the leaf is confined to the near vicinity of the growing 
points, hence an injury to the older part of the leaf is not 
repaired further than bj^ the formation of callus (73) over 
the wounded parts. 

122. The Cultivator Should Provide for Normal 
Leaf Development. Since the protoplasm of the plant is 
nourished by assimilated food (59), and since assimilation, 
iu most plants, takes place almost wholl}' in the leaves, it is 
of first importance that the plant be so cared for as to pro- 
mote normal leaf development. Without this, good crops are 
impossible. The plants must be grown far enough apart so 
as not to unduly shade each other; insects and fungi must 
not be permitted to prey upon them when it is possible to 
prevent it; and the leaves must not be needlessly removed 
or injured. 

123. How Far Apart Should Plants be Grown? 

When the finest developed plants, or parts of plants, as 
fruits, flowers, leaves, stems or roots is desired, the plants 
should not be grown so near together as to interfere with 
each other's leaf or root development. But when the largest 
crop from a given area is of more importance than the 
development of the individual plant, as with grain crops, 



8o Principles of Plant ( *ulture. 

the loss from a Limited amount of shade and crowding will 
be more than made up by the increased number of plants. 
In this case, the amount o\' crowding that will give the 
maximum yield will depend much upon the fertility and 
moisture of the soil, and must generally be determined by 
experiment. 

I'M. Stem and Root Development Depend on the 
Number of Leaves. Since the vascular bundles, through 
the formation of which the Stem and root increase in diame- 
ter, originate in the leaves (68), the size and firmness of the 
stem and root depend somewhat upon the number of leaves 
the plant hears. The more Leaves it has. the more solar 

energy it can transform into plant tissue. The stem is larger 
beneath a vigorous Leafy branch, and if cut off some distance 
above a branch, the part thus deprived of its foliage ceases 
to grow, unless it develops new Leaves. Trees growing in 
the dense forest, where their lower branches continually 
perish through lack of Light, have tall, but, very slender 

trunks, and their wood is soft because it contains compara- 
tively Little fibrous tissue, while other trees o{' the same 
species, in the lull light of the open field, through the 
Large amount of solar energy absorbed by an immense num 
ber of leaves, develop massive trunks, of which the wood, 
being packed with fibrous tissue, is much stronger than 
that (A' the forest tree. 

125. The Comparative Size of Leaves on a given 

plant depends much on the water supply during their for- 
mation. The Leaves o( sap sprouts (22 1). that take an undue 
proportion o( water, are usually very Large, and in upright- 
growing plants, the leaves on the more nearly vertical 
shoots are usually larger than those on the horizontal ones. 



The /.fairs. Si 

The more vigorous the plant, the larger, as a rule, are its 
leaves, 

In plants grown from seed to secure new varieties, 
lar^c leaves may l>c taken as evidence Ot superior root de 
velopment, which implies capacity to endure drought and, 
therefore, hardiness. In the apple, the large-leafed varie 
ties are, as a rule, hardier than others, probablj because 
their vigorous roots supply the needed water during the dry 
season, enabling 'l"' tree to mature healthy wood and buds, 
which can pass severe winters unharmed 75). 

Crops grown for their leaves, as cabbage, lettuce, tobacco 
etc., are especially liable to be curtailed by drought, and 
hence should be given the culture that best promotes soil 
moisture, as abundant surface tillage and liberal manuring 
(232). 

126. Leaves are Usually Short Lived bec.-iusc they 
become clogged with those mineral matters taken up with 
the soil water, which are not used by the plant (64), and 
which do noi pass off in transpiration (75). In most annual 
plants (337), the older leaves become useless from this clog- 
ging, and die before the stem is fully developed, and in most 
perennials tin; leaves endure but a single season. In tin; 
so-called evergreen plants, in which the leaves are usually 
very thick, and are often well protected against evaporation 
by a very strongly developed cuticle (65), the leaves rarely 

live more Hum a few yen is. 

127. The Manurial Value of Leaves, that mature on 

the plant, is usually small, since; the more valuable fertiliz- 
ing materials they contain pass into the stem before the 
leaves ripen (171). The mineral matters contained in largest 
quantity by leaves are those that are not used by the plant, 
but have been deposited within them in transpiration (126). 



82 



Principles of Plant Culture. 



Section X. The Buds 



128. Buds. Each growing point (67) of the stem is, in 
most plants, protected with a covering of rudimentary 
leaves or leaf-scales, and a growing point, with its leafy or 
scaly covering, constitutes a hud. Aside from the growing 
point, which in the stem exists only in the bud, a bud is 
simply a part of the stem in which the leaves and inter- 
nodes are in the embiyo stage. 

A bud forming the apex of a shoot is called a terminal 
bud; one at the junction of a leaf with the stem (axil) is 
called an axillary or lateral bud (Fig. 35). 
In most perennial plants, the rudimentary 
leaves that form at the latter end of the 
growing season, near the terminus of the 
young shoots, are changed into bud-scales, 
which serve to protect the tender growing 
point within from excessive moisture and 
sudden changes in temperature. Axillary 
buds which have not yet formed leaves, 
are clothed with similar scales. Buds in- 
closed with scales are often called winter 
buds. To more effectually shut out water, 
the scales are coated in some plants, as the 
horse-chestnut and balm of Grilead, with a 
waxy or resinous layer, and to protect from too sudden 
changes of temperature, they are lined in other plants, as 
the apple, with a delicate cottony down.* 




Fig. 35. Buds 
L, lateral buds 
(After Barry.) 



* A vertical section of the onion bulb may be used as a magnified illustration 
of a bud as it appears in winter, and that of a head of cabbage, of a bud unfolding 
in spriDg. 



The Buds. 83 

129. Nature Provides very Early for the Next 

Year's Growth in perennial plants. With the expansion 
of each leaf, a tiny bud begins to form at its axil, destined 
if need be, to become a branch the following year. Some- 
times, however, especially in ver}' vigorous shoots, the 
embryo buds at the axils of the earliest-formed leaves 
remain undeveloped. The more rapid the growth of the 
shoot, the less developed, as a rule, are the buds. 

130. Branches Develop from Lateral Leaf=Buds 

(132). In trees and shrubs (woody perennials), the lateral 
buds do not usually push into growth until the spring after 
their formation, unless the terminal bud is injured. Indeed, 
they ma} r never push into growth. Some lateral leaf-buds, 
especially those most distant from the terminal bud, through 
wantr of light or nutriment, usually remain dormant, and 
are overgrown bv the enlarging stem the following year. 
Such overgrown buds, stimulated b} T destruction or injury 
of the stem above, sometimes push into growth years after 
their formation. 

We can usually decide if detached dormant shoots of trees 
and shrubs, as cions (379) and cuttings (358) are of the pre- 
ceding 3 T ear's growth or older, since, as a rule, only wood 
formed the preceding year has visible undeveloped buds, 

131. Adventitious (ad-ven-ti'-tious) Buds. Although 
buds are normally formed 011I3- at the nodes of the stem, 
they ma} T , under the stimulus of unusual root pressure (102), 
be formed without" regard to nodes. The trunk of a vigor- 
ous elm. willow or horse-chestnut tree, cut off early in the 
season, often develops a multitude of buds from the thickened 
cambium at the top of the stump, and a circle of shoots 
often springs up about the base of a tree of which the top 



S4 Principles of Plant Culture. 

has been injured by over-pruning or severe cold. Such 
buds are called adventitious. It is, however, often difficult 
or impossible to distinguish between adventitious buds, and 
those that have been previousl} 7 overgrown (130). 

The roots of man}* plants, as the plum, cherry, raspberry 
etc., develop adventitious buds freely, especially when in- 
jured, a fact often utilized in propagation by root cuttings 
(376). 

132. Leaf=Buds,== Flower=Buds. Buds may contain 
only rudimentary leaves, or the}* ma}* contain rudimentary 
flowers, with or without leaves. The former are called leaf- 
ox toood-buds, the latter flower- or fruit-buds. Flower-buds 
are modified leaf-buds. Both originate in the cambium 
layer, and are normally located at the apex of the stem, or 
in the axil of a leaf (128, 129). 

133. FIower=Buds are often Readily Distinguished 
from Leaf=Buds, by location and appearance, the same sea- 
son in which they are formed, which enables the fruit grower 
to anticipate his crop. In the peach and apricot, and in 
some varieties of the plum* a flower-bud is normally formed 
on each side of the leaf-bud in the young shoots of bearing 
trees (Fig. 36). In the apple and pear, the flower-buds are 
less definitel}' located, but are mostly formed on the short, 
thick, wrinkled, and crooked branches from wood three or 
more years old (fruit spurs) (Figs. 41, 42). In some fruits, 
as the apple, cherry and peach, the flower-buds are usually 
thicker and more rounded than the leaf-buds, especially to- 
ward spring. Close and persistent observation will enable 
the horticulturist to early distinguish the flower-buds in 
many of his perennial plants. 

* Certain varieties of Prunus angustifolia and Prunus triflora. 



The Buds. 



85 



In the apple and pear, the buds on the so-called fruit- 
spurs are not necessarily flower-buds, but some seasons all 
are leaf- buds. How early in the life of the bud its 
character is fixed, or if flower-buds ever change to 
leaf-buds before expanding, does 
not appear to be known. The fact 





Fig. 36. Fig. 37. Fig. 38. Fig. 39. Fig. 40. 

Fig. 36. Flower-buds of Pottawattamie plum, Prunus angustifolia. The cen- 
tral bud of each group is a leaf-bud. 

Fig. 37 Fruiting branch of European plum, Prunus domestica. B, young 
wood. A, wood of preceding year. S, fruit spurs. 

Fig. 38. Fruiting branches of Morello cherry, Prunus cerasus. B, young 
wood. A, wood of preceding year. F, clusters of fruit- buds. 

Fig. 39. Leaf-buds of the apple. 

Fig. 40. Fruit-bud of apple (F). 

All are reduced one-half. (Figs. 37, 38, 39 and 40 are after Barry). 

that leafy shoots sometimes grow out of the center of flow- 
ers, and that petals (143) are sometimes developed as leaves, 
suggestthat such a change may occur. 

134. The Comparative Vigor of Leaf=Buds on a 

given shoot depends upon their location, and the length and 
diameter of the internodes. The terminal bud, when unin- 
jured, is usually the most vigorous one, and the vigor of the 



86 



Principles of Plant Culture. 



buds usually diminishes as we recede from the terminal bud. 
On a given plant, the buds are usually less vigorous on 
shoots having very long and thick internodes, i. e., the 
shoots that grew very rapidly (118), than on shoots with 
internodes of average length and thickness (129). 





Fig. 41. Fruit spurs of the apple. 
A, points at which apples were de- 
tached the preceding year; W, wrink- 
les, marking points at which fruit and 



Fig. 42. Fruit spur of the pear. Re- 
duced one-half. (After Barry). 

Cions (379) or cuttings (358) 
of dormant wood should be 
made from shoots having inter- 
nodes of average length and 
thickness and with plump and 
well-matured buds. 

In the potato tuber, which is 

leaves were detached in previous tlie thickened terminus Of an 

years. (After Hardy). 

underground stem, (Fig. 32) 
the most vigorous shoot comes from the terminal bud (the 
so-called " seed-end "), hence rejecting this part of the tuber 
in planting, as has often been recommended, is detrimental 
to the crop. 

135. Conditions Affecting the Formation of Flower= 

Buds. The majority of cultivated plants are grown either 
for their flowers or the product of their flowers, i. e., fruit 
or seed. But the flower is not an essential part of the plant 



The Buds. 87 

and instead of contributing to its welfare, as do the leaves 
and roots, it actually consumes a part of the plant's reserve 
food (140). As might be expected, therefore, perennial 
plants do not always produce an annual crop of flowers, 
even when well developed in other directions, hence the 
grower is often disappointed. Since flowers can only come 
from flower-buds, a knowledge of the laws that govern the 
formation of these would be invaluable to the cultivator. 
Unfortunately, this subject has received less attention than 
its importance deserves. Two principles ma} T be cited, 
however, which if the} T do not explain all the phenomena 
connected with the formation of flower-buds, are of sufficient 
general application to have great economic value, viz: 

A. — Plants form flower-bads only lolien they contain reserve 
food (85). 

B. — A icater supply Insufficient for rapid growth may suffice 
for abundant assimilation (50). 

In support of the first of these propositions, we mention : 

(a) Rapidly growing plants rarely form many flower-buds 
because the food is used up in growth as fast as formed. 

(b) Checking such rapid growth, 03' removing the growing 
points of the stem or root, or by withholding water, results 
in an accumulation of food, and is often followed by an 
abundant formation of flower-buds. (c) Obstructing the 
rootward current of assimilated food (80), as by " ringing " 
(138), causes an accumulation of food above the obstruction, 
and is often followed by the formation of flower-buds in 
that part. 

In support of the second proposition we mention: (a) 
Tlorists often bring their plants into bloom at a desired 
time by withholding water, (b) The flower-buds of most 
out-door plants are formed during the drier part of sum- 



88 Principles of Plant t ullure. 

mer,* when a restricted water supply prevents rapid growth^ 
but when abundant Bunlight and fully expanded foliage 
favor assimilation (59), 

We may infer, therefore, that treatment that furors the ac- 
cumulation of reserve food promotes the formation of flower' 
buds, a proposition that is homo out by the experience of 
practical cultivators. 

136* How can we Promote the Accumulation of Re- 
serve Pood? Three general principles may be cited: 

A. — Provide for ahum/ant assimilation by giving sufficient 
light and air and by protecting the foliage from the attacks 
o\' insects and fungi (Chap. 111. Section VI). 

B. — Provide sufficient plant food in the soil to satisfy all 
requirements of assimilation (Chap. Ill, Section V). 

C, — Provide for a moderate check to growth after the proper 
amount ot growth has been secured. 

In the greenhouse, where conditions are under control, 
these principles are readily followed, and the skilled tlorist 
rarely fails to secure bloom at the proper time. He gives 
the desired check to growth by permitting the roots to 
become densely matted in the pot (pot-bound), by with- 
holding water, or by pinching the tips of the more vigorous 
shoots. With out-door, perennial plants, as fruit trees, the 
problem is more difficult, since conditions are less under 
control than with plants under glass, but the principles just 
cited should always be kept in mind and carried out so far 
as possible. 

We can give sufficient light and air by planting the trees 
a sufficient distance apart (23) and by proper pruning 
(Chap. IV, Section III). 



• Plants that live over winter and bloom in spring, as the apple, strawberry 
eti . form their Bower buds the preceding summer. 



The Buds. 89 

II' the soil is properly drained, the natural depletion of 
soil water about midsummer will usually give the needed 
check to growth. In wet seasons, the drying of tin; soil may 
be promoted by stopping cultivation before midsummer and 
sowing a crop that will increase evaporation from the soil. 
as outs, clover or buckwheat. 

1!>7. In certain cases, as with seedling trees, of which 
we would early know the quality of the fruit, we may give 
an abnormal check to growth by pinching tin- tips of* the 
young shoots or by root pinning (416). These operations 
should be performed early in summer, before the period of 
flower-bud formation, and if the tree is not too young, flowers 
and fruit may be expected the following season. Frequent 
transplanting of .young trees aets like root pinning. cspc-i 
ally if the tap-root is severed. Such harsh measures, how- 
ever, while they promote early fruiting, doubtless tend to 
shorten the lite of trees. 

ItfS. Ringing (416) often Causes the Formation of 
Flower=Buds in otherwise barren trees, by obstructing the 

roofward current of assimilated food. Twisting a small wire 
about the branch, violently twisting the branch itself, or 
simply bending it to an unnatural position, arid fastening it 
there, answers tin; same purpose;. But these devices prob- 
ably weaken the tie*- and shorten its life by robbing the 
roots of their normal food supply and are excusable only 
in special eases, as with seedling trees. It is generally a 
reproach to the care of the cultivator, if his trees of bearing 
age cannol form flower-buds without such choking. 

Fruit trees grafted on slightly uncongenial stocks some 
times flower and fruit more freely for a time than when 

growing on their own roots, because the union of cion and 
a 



90 Principles of Plant Culture. 

stock (379) forms an obstruction to the rootward food- 
current. 

Section XI. The Flower 

1 39. The Flower is the developed and expanded flower- 
bud (132). Its oilice is to provide for the formation of new 
plants of its kind (reproduction (16)). Some plants, as the 
quack grass,* Canada thistle t and horseradish % multiply 
freely in nature without the aid of flowers, and nearly all 
plants may be multiplied in culture by other means, but in 
most of the higher plants, the flower is the natural organ of 
reproduction, and the only organ devoted solely to this end. 

14:0. Flowers Tend to Exhaust the Plant, since 
the}' are formed from the food assimilated by the leaves. 
But since flower-buds are not usually formed until the needs 
of growth are provided for (135), the normal production of 
flowers is no detriment to the plant. In certain cases, how- 
ever, as in plants weakened b} T recent transplanting, or in 
cuttings (358), flower-buds should be removed as soon as 
discovered, to prevent their exhaustive influence. 

141. The Parts of the Flower. The complete flower 
is composed of four different parts or organs. A knowledge 
of these parts is of great importance to the bor.anist in 
determining species, and also to the plant breeder who 
would practice cross-pollination (153, 441), hence we need 
to consider them in detail. The cherry blossom, of which a 
vertical section appears in Fig. 13, will serve as our first 
example. 

14'2. The Calyx (ca'-lyx). Beginning at the bottom, 
the part marked C in the figure, and which is green in the 

* Agropyrum rep$tts. t Onicus aroensis. .;: Nasturtium Armoracia. 



Thr Flower. 



9* 




Fig. 13. Section of cherry blossom 
corolla; 8. stamens. (After sjsjsj; 



Donna] cherry flower, is culled the calyx. In some plants, 
us the flax, the calyx is composed of several distinct, more 

o t 1 e s s Leaf-like 
parts, each of which 
is called u sepal (se- 
pal). In the cherry 
blossom, the sepals 
are united Dearly to 
He- top. The calyx 
is usually, but by no 
means always. green. 
In the tulip and 
many other flowers oi this class, it is generally colored like 
the corolla. In the apple and pear, the calyx becomes a 
part of the fruit, and its points are visible in the basin of 
the fruit, i. e., tin; depression opposite to the stem. 

14l>. The Corolla (co-rol'-la). Tin; more spreading 
part of the cherry blossom, normally colored white (Cor., Pig. 
\v>) constitutes the corolla. In tin? cherry, the corolla consists 
of five distinct parts, only three of which appear in tin; figure, 
called petals (pet'-als). In many plants, us the pumpkin 
and morning glory, the petals ure united into one. In other 
plants they ure united part way to the top. The corolla is 
usually, but not always, some other color than green. 

144. The Stamens (sta'-mens). Inside the corolla, is 
a group of slender organs (8. 8., Fig. t3) called stamens. Each 
stamen consists of three parts, viz.. the long und slender por- 
tion, connected with the calyx below, culled the filament 
(nT-a-ment); the swollen part ut the top. called the anther 
(an'-ther,); and the yellow dust, found within the anther, 
called the pollen (pol'-len). Each grain of pollen is a single 



9 2 



Principles of Plant Culture. 



cell, which if fertile (153), contains living protoplasm. The 
pollen is set free at maturity. 

145. The Pistil (pis'-til). The column-like part in the 
center of the flower is called the pistil. This also consists 
of three principal parts, viz., the enlarged flattened summit, 
called the stigma (stig'-ma); the egg-shaped base called the 
ovary (o'-va-ry); and the slender part connecting the two, 
the style. The ovary contains a smaller, egg-shaped part 
called the ovule (o'-vule), which when developed becomes 
the seed. Many flowers have more than one pistil. 

Recapitulating, the parts of the flower are, in the order 
we have considered them: 

a — The calyx ; when divided, the parts are called sepals. 
b — The corolla; when divided, the parts are called petals. 
c — The stamens; the parts are the filament, anther and 

pollen. 
d — The pistil or pistils ; the parts are the stigma, ovary 

and style. 

The ovar}^ contains the ovale or ovules. 

146. The Parts of the Flower Vary in Form in dif- 
ferent species. In the pea flower, (Fig. 44), the five petals, 

shown separately 
in Fig. 45, are not 
only quite unlike 
the petals of the 
cherry flower, 
but as appears, 
they are unlike 

Fivi. 44. Fig. 45. 

Fig. 44. Flower of the pea, Pisum sativum. (After eaCU Other. llie 

Ba i llon) ' B ,. , . stamens (Fig. 46 

Fig. 4o. The same dissected, showing variation in 
form of the petals. (After Figuier). St.), and the pis- 




The Flower. 



93 



tils (Fig. 4*7) of the pea are also quite different in form 
from those of the cherry. The variety of form in the parts 
of the flowers of different species is almost infinite. 

147. Certain Parts of the Flower are often Wanting. 
The flowers of the maple have no corolla; those of the wil- 
low have neither calyx nor 
corolla; certain flowers of 
the pumpkin, Indian corn 
and many other plants have 
no stamens, while other flow- 
ers of the same species have 
no pistils (154). In man}' 
varieties of the American 
plum (Prunus Americana) the 
pistil is often wanting. 




148. Composite (com- 
posite) Flowers* are made 
up of several individual flow- 




Fig. 48. Cross section of flower-head of sunflower, 
Helianthus annuus. Reduced. The florets appear 
closely crowded in the center of the head. 



Fig. 46. Fig. 47. 

Fig. 46. Stamens (st) and pistils- of 
the pea, Pimm sativum. 

Fig. 47. Pistil of same alone. (After 
Baillon) 

ers in the same flow- 
er-head. The sun- 
flower (Fig. 48) is a 
familiar example of 
a composite flower. 
One of the separate 
flowers is shown in 
Fig. 49. At the 
outer edge of the 
flower head, is a row 
of individual flow- 
ers, each of which 



* The plants having composite flowers form an extensive family in botany called 
Composite. 



94 



Principles of Plant Culture. 



has a long, 3-ellow, petal-like appendage (Fig. 50) called a 
ray. The flowers bearing rays, are called nvy-flowers. Some 
composite flowers are without ray-flowers, as, e. g., the tansy, 
(Tanacetum vulgar e). 

149. The Flowers of the Grass Family (Graminere), 
to which the cereals belong, as well as corn, sorghum, sugar 

cane etc., are quite different from 
those of most other plants. In this 
family, the flowers are arranged in 
little groups, each of which is called 
a spikelet. What we call a head 
of wheat is made up of a number 
of spikelets, one of which is shown 
in Fior 51. Fig. 52 shows the 
spikelet dissected. The two 




Fig 49. 
Fig. 49. 
Fig. 50. 



Fig. 50. 

Floret of sunflower. 
Ray-flower of same. 



b^' 






sv- 



Fig. 58, 



Fig. 51. Fig. 52. 

Fig. 51. Spikelet of wheat; st. stamens. (After Lamout and Deeaisne). 

Fig. 52. The same dissected, x, axis of spikelet; g. glumes; bl, b2, outer pales; 
Bl, B2, flowers displaced from the axis of outer pales; p s, inner pales; a, anthers; 
f, ovary. (After Prantl). 

Fig. 53. Flower of wheat, enlarged; st. stamens; p, pistil; o, ovary. (After 
Lamout and Deeaisne). 

scale-like parts at the base, g. g. are called glumes. The 
similar pair above, tipped with a bristle (the awn or beard) 
are called the lower or outer pales or palets (pa'-lets) or flow- 



The Flower. 95 

ering glumes — to distinguish them from the smaller and 
more delicate upper or inner palets which are just above 
and inclosed within the outer palets. Between the outer 
and inner palet, are the stamens and pistils, shown sepa- 
rately in Fig. 53. 

1 50. Fecundation * (fec'-un-da'-tion) is the union of the 
male and female cell by which the new plantlet is formed. 
The ovule produces within itself a female cell which must 
be fecundated by the male cell produced by the pollen (144). 
This fecundated cell then grows to form a young plant, — the 
embryo (54); and the parts of the ovule develop about it, 
the whole forming the perfect seed. Unless the ovule is 
fecundated, the seed very rarel}' develops. A flower that 
contains no pistil, and hence no ovule, can of course produce 
no seed. 

151. Pollination (pol-lin-a'tion), is the application of 
pollen (144) to the stigma (145) — the first step in the pro- 
cess of fecundation. During a certain period, the surface 
of the stigma is moistened by the secretion of a viscid 
liquid, to which the pollen grains readily adhere. Fertile 
pollen grains, alighting on the stigma of sufficiently near- 
related plants, during this period undergo a process com- 
parable to germination, in which a slender projection 
from the pollen cell penetrates the stigma, passes length- 
wise through the center of the style and enters the ovule, 
where fecundation occurs. 

In some flowers, as in the pea, the stigma is brought into 
direct contact with the pollen by the elongation of the 
style, but in most plants, the pollen must be transferred to 

*The term fertilization, that has been commonly used for this process, tends 
to confusion, because fertilization is also applied to the addition of plant food to the 
soil. 



96 Principles of Plant Culture. 

the stigma by some outside influence, as by insects or the 
wind, or by gravity. Most flowers which have a showy corolla 
or calyx, or secrete nectar, or yield a fragrant perfume, 
depend largely upon the visits of pollen-loving or nectar- 
loving insects for pollination. The show\ r parts, and the 
perfume serve as signboards to direct the wandering insects 
to the flowers. 

152. Cross Pollination occurs when the stigma is pol- 
linated with pollen from a different plant, especially from a 
plant of a different variety or species (21). The fecunda- 
tion resulting constitutes a cross or hybrid, as the case may 
be (23). Cross pollination is often performed artificially (441). 

Close- or self pollination occurs when the stigma receives 
pollen from its own flower or plant. 

153. Cross Pollination is Advantageous in Plants, as 

Darwin's careful experiments have shown. The seeds 
formed are usually more numerous and larger, and form 
more vigorous plants, than with close pollination. Es- 
pecially is this true when the parent plants have been sub- 
jected to different growth conditions in previous generations. 
Nature favors cross pollination in perfect-flowered plants 
hy numerous adaptations tending to prevent self pollina- 
tion, as maturing the pollen either before or after the recep- 
tive stage of the stigma, or so locating the stamens that the 
pollen is not readily deposited on the stigma of the same 
flower.* In some cases, pollen is infertile on a stigma of the 
same flower or plant that is abundantly fertile t on stigmas of 
other plants of the same species (155). 



♦Darwin's work "On the Various Contrivances by which Orchids are Fertil- 
ized by Insects" describes many most interesting adaptations of this sort. 

f Fertile pollen is pollen that is capable of fecundating female cells of its own 
sp?cies. 



The Flower. 



97 



154. Perfect, Monoecious (rno-noe'-cious) and Dioecious 

(di-ce'eious) Flowers. Flowers containing both stamens and 
pistils (or pistil), as in the apple, tomato, cabbage, etc., are 
called perfect or hermaphrodite (her-maph'-ro-dite) ; those con- 
taining but one of these organs as in the melon, Indian corn, 
etc., are called imperfect or unisexual (u'-ni-sex'-u-al).* 
Flowers of the latter class are called monoecious when the 
stamen-bearing (staminate (stam'-i-nate)) and pistil-bearing 
(pistillate (pis'-til-late)) flowers are both produced on the 
same individual plant, and dioecious when produced on differ- 
ent plants only, as in the hop and date. In a few plants, as 
the strawberry (155) and asparagus, some individuals pro- 
duce perfect, and some imperfect flowers. 

155. Planting with Reference to Pollination is im- 
portant in certain plants. All dioecious plants (154) in- 
tended for seed or fruit must have staminate and pistillate 
plants growing near together or the} 7 will not be productive. 
The hop plant and date palm are of this class. 

The flowers of many 



of our most productive 
varieties of strawberry 
yield little or no pollen, 
and are unproductive 
unless growing near 
pollen-bearing sorts 
(Figs. 54, 55). In many 
varieties of American 
plums, and in certain 




Fig. 54. Fig. 55. 

Fig. 54. Imperfect flower of the strawberry. 

Fie. 55. Perfect flower of same. The nu- 
merous pistils appear iu a circular mass at the 
center, arouud which the stamens are seen in 
Fig. £5. 

varieties of the pear, the pollen, even though produced 
freely, is infertile on stigmas of the same variety. To insure 



*The terms hermaphrodite, unisexual and bisexual, though often applied to 
flowers, are hardly accurate. 



98 Principles of Plant Culture. 

fecundation, it is wise to mingle varieties in fruit plantations 
rather than to plant large blocks of a single variety. 



Section XII. The Fruit and the Seed 

1 56. The Fruit, as the term is used in botany, is the ma- 
ture ovary, with its contents and adherent parts; it may be 
hard and dry, as in the wheat and bean, or soft and pulpy as 
in the apple and melon. But in common language the term 
fruit is limited to the pulpj T and juicy part of certain plants 
that normally contains or supports the seed or seeds. To 
avoid explaining botanical terms, we use the word in the 
latter sense. In this sense, the fruit serves the plant by 
attracting animals that can assist in disseminating the seed. 

The seed, as we have seen (145), is the fecundated and 
mature ovule, and its normal office is reproduction (16). 

157. Fruit Rarely Develops without Fecundation 

of the germ cell of the ovule (150). Varieties of the apple 
and pear have, however, appeared in which the pulp de- 
velops without seeds. The fruit of the banana is almost in- 
variably seedless. The cucumber, grape and fig sometimes 
develop their fruit without fecundation of the germ cell. 
But these instances are all exceptions to the general rule. 

158. Seed Production Exhausts the Plant far more 
than other plant processes. The seed assimilates little or no 
food, while it removes from other parts of the plant a com- 
paratively very large amount of assimilated food, which it 
stores up in a concentrated form as a food supply for the 
embryo (55). Very many plants (all annuals and biennials) 
are killed the first time they are permitted to seed freel} 7 . 



The Fruit and the Seed. 99 

and perennials are often much weakened b} r excessive seed- 
ing* 

159. Prevention of Seeding Prolongs the Life of 
Plants. Many annual flowering plants, as sweet peas, 
dianthus, etc., that soon perish when permitted to mature 
their seed, continue to bloom throughout the summer if 
the flowers are persistently picked. The yield of cucumbers, 
peas, beans and other garden crops of which the product is 
gathered immature, may be considerably increased b} T pre- 
venting the ripening of seed. 

160. Overbearing Should be Prevented. Certain va- 
rieties of some of our cultivated fruits, as of the apple, 
plum and peach, tend to devote an undue amount of their 
reserve food to fruit and seed production in fruitful seasons, 
which, if permitted, results in enfeeblement or premature 
death. The wise cultivator guards against this tendency by 
thinning the fruit before it has made much growth, thus sav- 
ing the tree from undue exhaustion and greatly improving 
the quality of the fruit allowed to mature. 

Thinning should be done as early as the fruits can be 
properly assorted, and the more imperfect ones should alwa} T s 
be removed. The proper amount of thinning will depend 
upon many conditions, as age and health of tree, abundance 
of crop, fertility of soil, water supply, etc. It must be de- 
termined by judgment and experience. 

161- The riaturing of Seed Injures Fodder Crops. 

The food value of straw, from which the ripe grain has been 
threshed, is comparatively small, and that of grass and 



* Double-flowered varieties of the annual larkspur (Delphinium), that bear no 
seed, have become perennial. 



ioo Principles of Plant Culture. 

other crops, intended tor coarse fodder, is much reduced by 
permitting- the seed to ripen before cutting. 

1(J'2. The Ripening; of Fruits. Green fruits assist the 

i 

leaves in assimilation to some extent, but as they begin to 
ripen, the process is reversed. Carbonic acid and wafer are 
then given off, while oxygen is absorbed. Fruits first be- 
come sour from the production of acids. These disappear 
in part at a later stage, while sugar is notably increased. 

Some fruits, as the strawberry and peach, increase rapidly 
in size during the ripening period, provided the water supply 
is sufficient 

Most fruits that have attained Dearly normal size, ripen to 
a degree when detached from the parent plant, Tears are 
usually improved in quality it" picked before maturity and 
ripened in-doors. The grape, however, fails to develop its 
sugar if prematurely picked. 

Section Kill. The Gathering am> Storing of Seeds 

1(>;{. The Stage of .Maturity at which Seeds will 
Germinate varies greatly in different plants, and bears no 

direct relation to the time at which the seeds are set free 
from the parent plant. Seeds of the tomato will germinate 
when the fruit is little more than half grown, and those 
of the pea will germinate when tit for table use. On the 
other hand, seeds of the thorn (Cratcegus) and juniper 
rarely germinate until the second spring after their produc- 
tion. Seeds of many annual and biennial plants, as the 
cereals, cabbage, etc.. may germinate as soon as set free by 
the parent plant, but those of many annual weeds, and ol' 
most trees and shrubs, will not germinate until some months 
afterward. 



The Gathering' and Storing of Seeds. 101 

Seeds necessarily gathered immature will often ripen suf- 
ficiently for germination if a considerable part of the plant 
is plucked and cured with them. 

164. Immature versus Ripe Seeds. Seeds not fully 
grown lack a part of their normal food supply, and their 
embryo is probabh* imperfectly developed. If capable of 
germination, they rarely, if ever, produce vigorous plants. 
As a rule, the most vigorous plants come from fully matured 
seeds. Immature seeds, persistently used, probably tend to 
reduced vigor, early maturity, dwarfness and shortened 
life. In some over-vigorous plants, as the tomato, slightly 
immature seed ma} T tend to increased frnitfulness. 

Slightl}' immature seeds usually germinate sooner than 
fully matured ones. 

165. The Vitality of all Seeds is Limited by Age, 
but the duration of the vital period varies greatly in differ- 
ent species. Seeds of the chervil rarely germinate if much 
more than one year old, while those of the gourd family, and 
of the tomato and celeiw often germinate well when ten 
3'ears old. As a rule, oily -seeds, as of Indian corn, rape 
and sunflower, are shorter lived than starchy seeds, as 
wheat and rice. The following table* gives the average 
period during which the seeds named are reliable for ger- 
mination, when properly cared for : 

Duration of Duration of 

Germinating Power . GerminatiDg Power. 

Average. Extreme. Av. Ext'm. 

Years. Years. Yrs. Yrs. 

Artichoke 6 10 Cauliflower 5 10 

Asparagus 5 8 Celery S 10 

Bean 6 10 Chervil 2 or 3 6 

Bean — Kidney 3 8 Chervil, Sweet-scented 1 1 

Bean — Soy 2 6 Chervil, Turnip-rooted 1 1 

Borecole or Kale o 10 Corn Salad 5 10 

Broccoli 5 10 Cress, American 3 5 

Cabbage 5 10 Cress, Common Garden s 9 

Cardoon 7 9 Cress, Water 5 9 

Carrot 4 or 5 10 Cucumber, Common 10 10 

* From "The Vegetable Garden," Vilmorin, Andrieux & Co., Paris. 



102 Principles of Plant Culture. 

Duration of Duration of 

Germinating Power. Germinating Power. 

Average. Extreme. Av. Ext'm. 

Years. Years. Yrs. Yrs. 

Eggplant 6 10 Parsnip 2 4 

Endive 10 10 Parsley 3 9 

GuiobjorOkra 5 10 Pea 3 8 

Hop 2 4 Pumpkin 6 10 

Kohl-Rabi 5 10 Rhubarb 3 8 

Leek 3 9 Salsafy 2 8 

Lentils 4 9 Sea-kale 1 7 

Lettuce ft 9 Spinach (Prickly-seeded) ft 7 

Maize or Indian Corn 2 7 Squash 6 10 

Melon — Musk 5 10 Strawberry 3 6 

Melon— Water 6 10 Tomato 4 9 

Mustard, Black or Brown 4 9 Turnip 5 10 

Ooion 2 7 

166. Conditions Affecting the Duration of Seed Vi= 
tality. A uniform degree of humidity and temperature, by 
causing little drain upon the life of the living cells, tends 
greatly to prolong the vital period of seeds. Seeds deeply 
buried in the ground are often capable of germination at a 
great age, and kidney beans at least one hundred years old, 
taken from an herbarium, are said to have germinated. In 
these cases, the seeds were subjected to few variations in 
humidity and temperatare. 

Seeds usually retain vitality longer when not removed 
from their natural covering, probably because they are thus 
exposed to fewer changes of humidit} 7 and temperature. 
Timoth} T seeds, that become hulled in threshing, lose vitality 
sooner than those that escape hulling, even when the two 
sorts have been kept in the same bag. Indian corn is said 
to retain vitality longer on the cob than shelled, and longer 
when the ear is unhusked than if husked. 

167. Moisture is an Enemy to Stored Seeds except 
for the class that requires stratification (170). A little 
moisture in stored seeds is very liable to cause the develop- 
ment of fungi (moulds) that may destroy the embryo. Damp 
seeds are also liable to be destroyed bv freezing. It is im- 



The Gathering and Storing of Seeds. 103 

portant that seeds be dried promptly after gathering, for if 
mould once starts, subsequent drying may not destroy the 
fungus, but it ma}' resume growth as soon as the seed is 
planted, thus enfeebling or destining the embryo before it 
has time to germinate. Drying by moderate artificial heat 
(not higher than 100° F.) is wise with seeds necessarily gath- 
ered in cold or damp weather. 

Oily seeds, as of Indian corn, sunflower, and the cabbage 
family, (cabbage, cauliflower, kohl-rabi, ruta-baga, rape, 
turnip, mustard) cannot safely be stored in bulk in large 
quantities, except in cool weather. 

Seeds are much shorter-lived in warm than in cold cli- 
mates. 

The most satisfactory method of preserving seeds in 
quantity is to inclose them in bags of rather loose texture, 
and of moderate size, and to store these in a cool, dry and 
airy apartment. 

168. Age of Seed as Affecting the resulting Crop. 
Seeds grown the same or the preceding season produce, as a 
rule, more vigorous plants than older seeds. The}' may not. 
however, in all cases, produce plants that are most product- 
ive of fruit or seed, for excessive vigor is generally opposed 
to reproduction. Cucumber and melon plants grown from 
seed three or four years old are often more fruitful than 
those from fresh seeds. In crops grown for parts other 
than fruit or seed, fresh seeds are undoubtedly preferable, 
but in crops grown for seed or fruit, it may be doubted if 
fresh seed will always give as large returns as seeds of some 
age. This subject needs further investigation. 

169. How Drying Seeds Affects their Vitality. The 

vigor of seeds is probably uever increased by drying them, 



104 Principles of Plant Culture. 

but the seeds of most annual and biennial plants may be- 
come air-dry without material loss of vitality. The seeds 
of very man} 7 shrubs and trees, however, lose vitality rapidly 
by such drying, and, of some species, are destroyed by it. In 
nature, seeds of the latter class are usually dropped from 
the parent plant before becoming dry, and are soon covered 
with leaves or other litter that keep them moist. Nursery- 
men either plant such seeds as soon as they are ripe, or else, 
if of species that do not germinate as soon as ripe, they im- 
itate nature by the process known as 

170. Stratification of Seeds. This consists in mixing 
the freshly-gathered seeds with moist sand, taking care that 
the sand is kept moist until the time for sowing arrives. 
Large quantities of seeds may be stratified in boxes, by 
placing the moist sand and seeds in alternate layers, or 
the layers may be built up in a pile on the ground. The 
sand should be coarse enough to admit some passage of air 
between the particles, and to give perfect drainage. The 
layers should not much exceed an inch in thickness, except 
for the larger seeds, and the number of layers should not 
be so large as to prevent proper aeration of the mass. Small 
quantities of seeds ma} 7 be mixed with sand or porous loam, 
in flower-pots. Moisture may be maintained in the boxes or 
pots by burying them a foot or more deep in the soil, in a 
well-drained place, or by storing them in a moist cellar. 
Care is necessary to keep mice and other vermin from strat- 
ified seeds. It is well to cover pots in which valuable seeds 
are stratified, with a sheet of tin or zinc, and metal labels 
are best for distinguishing different sorts of seed. The 
seeds should remain stratified until sowing time, when they 
may be sifted out of the soil, or sown with it, as is more 



Decline of Growth and the Rest Period. 105 

convenient. Seeds that do not germinate well until the 
second spring after maturity (163) are commonly left in 
stratification until that time. 

Section XIV. The Decline of G-rowth and the 
Rest Period 

171. Annual plants usually perish soon after maturing 
their seed. In other plants, a certain period of vital ac- 
tivity is followed by one in which growth gradually declines 
until it almost or entirely ceases. In woody plants, 
the cells become thickened and a part of the rudi- 
mentaiy leaves change to bud-scales, which inclose the 
growing point (128). In deciduous trees and shrubs, the 
chloroph} T ll and starch, with most of the potash and phos- 
phoric acid contained in the leaves are withdrawn into the 
wood}' parts, while the leaves themselves are detached and 
fall. The root-hairs also die, in many if not all plants. 
In perennial herbs, the nutritive matters in the foliage and 
stem are withdrawn to the underground parts. A period of 
almost complete repose ensues, during which the plant, 
owing to the dormant condition of its protoplasm, is able to 
endure without harm, extremes of temperature or dryness 
that would be fatal in its active state. 

172. The Rest Period is Not Peculiar to the Temper= 
ate Zones, but occurs in the tropics as well. It cannot be 
ascribed wholly to the change of seasons, as a few familiar 
examples will indicate. Tubers of the earlier varieties of 
the potato, that ripen in the northern states by the begin- 
ning of August, do not sprout if left in the ground till Oc- 
tober, but if stored in a cellar, during winter, at a tempera- 
ture little above freezing, often begin to sprout in March. 

Bulbs of the crocus, tulip, narcissus, crown imperial, etc., 

7 



106 Principles of Plant Culture. 

that form in spring, lie dormant in the warm soil during 
summer and early autumn, but start vigorously in the colder 
soil of the late autumn or the succeeding spring. The buds 
of man} T trees that form in summer, for the next year's foli- 
age and flowers, remain dormant during the hot weather 
of August and September, to push vigorously in the first 
warm days of spring. The rest period is to be regarded as 
a normal, if not a necessary factor of plant life. 

173. Most Plants Under Glass Require Rest from 
time to time, or the} 7 do not thrive. This rest is provided 
either by placing them in a lower temperature than is favor- 
able to growth, or by submitting them to a degree of dry- 
ness that prevents growth. The latter is preferable for 
plants native in the tropics, where they naturally lie dor- 
mant during the diy season. 

174. The Time of Leaf Fall is an Index of Wood 
Maturity in deciduous trees and shrubs, In these, the color- 
ing and fall of the leaves in autumn is not necessarity due 
to frost, but, in hardy plants, results from the dormant con- 
dition that accompanies maturity. As a rule, the more 
mature leaves are precipitated by the first autumn frosts. 
Those less mature usually remain until the more severe 
frosts. In trees with well-ripened wood, the leaves at the 
tip of the shoots usually fall before, or not later than, those 
on the older parts of the tree. With poorly-matured wood, 
the reverse is the case. In a few deciduous trees, as the 
beech, and some oaks, many of the mature leaves remain 
on through the winter. 

17 5. Hardiness Depends upon the Degree to which 
the Dormant State is Assumed. Since the most severe 
climatic extremes come during the natural rest period of 



Decline of Growth and the Rest Period. 107 

plants, the abilit} 7 of the plant to endure these extremes de- 
pends upon the extent to which the protoplasm becomes 
dormant during the decline of growth. As a rule, a given 
plant is hardy (10) in a locality in which the duration and 
warmth of the growing season are sufficient to complete and 
f UU3' mature its normal amount of growth. Varieties of 
the apple, and other trees, that so far complete their growth, 
in any given locality, that their leaves fall before hard 
frosts, are rarely injured in winter, while those that continue 
growth until their foliage is destroyed by freezing suffer in 
severe winters. Deciduous trees in a climate where none of 
the leaves fall before hard frosts, as is the case with the 
peach, apricot and nectarine in the northern United States, 
must be regarded as tender and liable to destruction in 
severe winters. 

176. Individual Plants Cannot Adjust Themselves 
to a New Environment except to a slight extent. The 
power to complete the annual growth processes and become 
sufficiently dormant to endure the rigor of the rest period, 
in an} T given locality, is inherited, and not acquired. We 
are, therefore, able to do very little toward inuring or accli- 
matizing (ac-cli'-ma-tiz-ing) individual plants to an environ- 
ment to which they were not adapted by nature. We may, 
however, through the variations of offspring (18), secure 
varieties that can endure an environment that the parents 
could not endure. 

177; Plant Processes during the Rest Period may not 

entirety cease. Although assimilation is wholl}* suspended, 
root growth and the callusing (73) of injured root surfaces 
proceed to some extent during the winter, in unfrozen 
layers of soil; and in sufficiently mild weather, the reserve 



io8 Principles of Plant Culture. 

food in the stem gradually moves in the direction of the 
terminal buds. 

178. Cuttings (358) of Woody Plants are Prefer= 
ably Made in Autumn, in climates of severe winters, and 
buried in the ground below the limit of hard freezing, in 
order that callusing (73) and the transfer of food ma}' make 
some progress before the final planting. 

179. The "Turn of the Year." Toward the close 
of the dormant season, vegetation, as if benefited by the 
rest, is prepared to start with renewed vigor, even at moder- 
ate temperatures. Buds, that remained dormant during the 
latter part of the previous summer, push into growth with 
the first warm days of spring, and many seeds, that could 
not be induced to germinate the preceding autumn, start 
with vigor as soon as the soil is sufficiently warm. 

The cause for this vigorous resumption of plant growth, 
after the rest period, is not well understood, but the 
exposure to cold, in the case of temperate plants, and to 
prolonged dryness in that of tropical ones, doubtless 
explains it in part, for it is well known that potato tubers 
ma} T be induced to start their buds soon after maturit}- by 
exposing them to the sun a few da}-s, or by placing them 
for a like time in a refrigerator containing ice. By these 
means, farmers of Tennessee grow a second crop of potatoes 
in the latter part of summer and during autumn. 

Plants under glass usuall}- thrive better after midwinter 
than before, and the most favorable time to plant seeds of 
greenhouse plants is toward the close of the natural rest 
period. 

180. The Round of Plant Life we have now traced, 
from the first swelling of the planted seed, through the 



Decline of Growth and the Rest Period. 109 

development of the embryo into the plantlet, the penetration 
of the root into the dark and damp soil cavities, the absorp- 
tion and conduction of water with its food materials in solu- 
tion, to co-operate with the sunlight and carbonic acid, in the 
mysterious laboratory of the leaf, in building up the plant 
body into node and internode, bud, branch, flower, fruit and 
seed; through growth decline, leaf fall and winter sleep, to 
the renewed vigor of another springtime. 

In our study of the round of plant life, we have assumed 
the environment to be favorable. But in the practical cul- 
ture of plants, we are constantly meeting with adverse 
conditions of environment. Talent for plant culture lies in 
the ability to discern these adverse conditions by the 
appearance of the plant, and in knowing how to correct 
them. We will, therefore, next consider the plant as affected 
by unfavorable conditions of environment. 



The following books are recommended for reading in con- 
nection with the preceding chapter : "How Plants Grow/' 
Gray; " Lessons in Botan} 7 ," Gray; " Botanical Text-Book," 
Gray; " The Soil," King. 



CHAPTER III. 

THE PLANT AS AFFECTED BY UNFAVORABLE 
ENVIRONMENT 

181. Factors of Environment. The plant environ- 
ment is mostly comprehended under the terms, climate, soil, 
animals and other plants. But as these are more or less 
complex influences, it is well to anatyze them and to consider 
their component factors separately. 

Section I. The Plant as Affected by Unfavorable 

Temperature 

A — The Plant as Affected by Excessive Heat 

182. Transpiration Increases with the Degree of 

Heat. The most common effect of heat upon plants is the 
drooping of the foliage, due to excessive transpiration (75). 
With insufficient water, this may occur at a temperature that 
is normal for the plant. But with a water supply that is 
sufficient at ordinarj- temperatures, transpiration ma}' be so 
much increased by an overheated atmosphere that the roots 
are unable to supply the plant with water, and as the result, 
the cells become partially emptied and the foliage droops. 
Herbaceous plants in an overheated greenhouse or hotbed 
are sometimes so prostrated from excessive loss of water 
from their tissues as to appear dead. But unless the heat 
has been sufficient to destroy their protoplasm, they will 
recover when their normal temperature and water supply 
are restored. 



Plants as Affected by Heat. * in 

183. Evergreen Trees are sometimes Destroyed by 
Untimely Warm Weather in spring. With a soil so cool 
that the roots are inactive, a sudden rise of atmospheric 
temperature, especially if accompanied by a drying wind, 
may so far reduce the water in the leaves of evergreen trees 
as to cause death of the foliage, and even of the trees them- 
selves. This most frequently happens in the seed-bed, in 
compact nursery plantations, or with recently-transplanted 
evergreen trees. It is most' disastrous on poorh'-drained, 
clay soils that have a southwesterly exposure, and at times 
when the ground is deeply frozen. 

The preventives to be observed are, a, means that will 
prevent the tardy thawing of the ground, as thorough 
drainage, and not too close planting; 6, means that will pre- 
vent, in a measure, exposure to the sun, as planting on a 
northern slope, or shading the trees (414); c, means that 
tend to prevent the deep freezing of the soil, as providing 
wind breaks (204)^ which tend to retain the snow. 

184. A Temperature of 122 F. is Fatal to the 
Protoplasm of most land plants. Aquatic plants, and the 
more watery parts of land plants, perish at a somewhat 
lower temperature. Wateiy fruits, as tomatoes and goose- 
berries, and the 3'ounger leaves of deciduous trees, are 
sometimes destroyed by full exposure to the sun's rays in 
very warm weather. An occasional sprinkling of the plants, 
and of the soil about them, will usuallj 7 prevent this result. 

185. Plants Under Glass should Not be Sprinkled in 
Bright Sunshine. Drops of water upon the leaves of 
plants often act as lenses in converging the rays of the sun, 
and, in a closed greenhouse or hotbed, ma}' cause a heat 
that is fatal to the foliage beneath them. This may explain 



112 



Principles of Plant Culture. 



the brown spots so often observed upon the leaves of indoor 
plants that have been sprinkled in bright sunlight. Some- 
times, but rarely, this trouble occurs in the open air. 

186. Sun=scald is a term 
applied to an affection of the 
trunk and larger branches of 
certain not-fully-hardy trees, 
usually upon the south or 
southwest side, in which the 
bark and cambium la}'er are 
more or less injured (Fig. 57). 
In severe cases, the cambium 
is totally destroyed, and the 
loosened bark splits longitu- 
dinally or becomes detached. 
The effect is apparentl}' the 
same as when a tree is exposed 
to the heat of a fire. Sun-scald 
is most common in young trees 
and appears to be due, in some 
cases, to the superheating of 
the cambium in summer, — in 
others to a return of severe 
freezing weather after a period 
sufficiently warm to excite the 
cambium cells to activit} T . A 
preventive is to shade the trunk 
and larger branches by inclosing 
them with straw or similar ma- 
terial, 01' With a lath Screen *«flW«- Madison, Wis 

(Fig. 58). 




Fig. 57. Showing effects of sun-scaid 
on trunk of silver maple tree, Acer 



Plants as Affected by Cold. 



XI 3 



187. Potato Foliage is often Injured by Sun Heat in 

summer, as is shown by the browning of the leaves from the 
tip and edges toward the center, or on 
£/the border of holes made by insects. 
This affection, known as " tip-burn,'' is 
due to the destruction of the protoplasm 
in the cells, and is often mistaken for 
^the work of a fungus. It is most serious 
in dry seasons. No remedy for it is 
known, but it may be in part avoided by 
selecting varieties least subject to it. 

B — The Plant as Affected by Excessive 
Cold 

188. The Immediate Effect of 
Cooling the Plant is to check the ac- 
tivity of its vital processes. When a 
certain degree of cold is reached, the 
protoplasm loses its power to imbibe 
water (63); hence the plant tissues be- 
come less turgid, and the foliage droops 
somewhat. With a sufficient reduction 
iJjf of temperature, ice crystals form within 
$the tissues and the succulent parts of 

fig. 58. Ipple'tree in- the P lant assume a glassy appearance. 
cased in lath screen. The foliage of man} T plants, as celery, 

parsnip etc., assumes an abnormal position when frozen. 

189. The More Water Plant Tissue Contains, the 
Sooner it Freezes. Since the water of plants is not pure, 
but is a solution of various substances, it does not freeze at 
the freezing point of pure water (32° F.), but at a lower 




114 Principles of Plant Culture. 

temperature, determined by the degree of concentration of 
the solution, or the intimacy with which it is combined with 
the tissues of the plant. The more thoroughly dormant the 
condition of a plant, or part of a plant, the less water does it 
contain, and the better is it able to endure cold. 

190. The Power of Plants to Endure Cold depends 
upon various conditions, aside from the amount of water 
contained, as 

a — Heredity. Plants by nature possess widelj' differing 
powers to endure cold. The Anoctochilus (a-ncec'-to-chi'-lus) 
perishes when exposed for a considerable time to a temp- 
erature of 42° F., while other plants, as the common chick- 
weed,* are uninjured by prolonged cold, far below the freez- 
ing point. 

b — The rate of thawing of the frozen tissues. The more 
slowly the thawing takes place, the less likely is the frozen 
part to suffer injury. Many bulbs, tubers and roots which 
survive the severest winters, within the soil, where the}' thaw 
slowly, are destined by moderate freezing if quickly thawed. 
Frost-bitten plants are seldom injured when sheltered from 
the morning sun by a dense fog, which causes them to thaw 
slowly. Apples, covered in the orchard in autumn by leaves, 
sometimes pass a severe winter with little harm. 

When the water that is withdrawn from the tissues in the 
freezing process is gradually set free, by slow thawing, it 
may be absorbed by them again and little or no harm results. 

c — The length of time the tissues remain frozen. A compar- 
atively slight degree of frost, if prolonged, ma}' act more 
injuriously than a severer degree of shorter duration. Pro- 
longed freezing is especially injurious when the frozen parts 

* Stellaria media. 



Plants as Affected by Cold. 115 

are subjected to drying wind, which evaporates their water, 
while the frozen condition prevents movement of their fluids. 

d — The frequency ivith which freezing and thawing are 
repeated. Frequent slight freezing and thawing are far more 
injurious than a prolonged frozen condition, even at a much 
lower temperature. Winter wheat and rje, and strawberry 
beds are often more damaged in mild winters, in which 
freezing and thawing weather alternate, than in more severe 
ones, when the temperature is mostly below freezing. The 
chief damage is usually done to these crops in late autumn 
and early spring. 

e — The previous treatment of the plant. Plants grown by 
artificial heat may be far less able to endure cold than 
others of the same varieties grown in the open air, possibly 
owing to the more succulent condition of the former. 
Gardeners "harden" plants grown under glass, by gradually 
exposing them to the cooler out-door atmosphere, before 
removing them to the open ground. 

f — The treatment of the frozen tissues. Handling plants, 
fruits or vegetables while frozen greatly aggravates the 
damage done by the frost, probably because the handling 
increases laceration of the cells by the ice crystals within 
them. 

191. Frost=Injured Plants, Fruits or Roots May 
often Be Saved from serious damage, if promptly placed 
under conditions that cause the slowest possible thawing of 
the tissues, as shading from the sun's rays, immersing in ice 
water or covering with snow. They should be handled as 
little and as carefully as possible while frozen. The mere 
sprinkling of cold water often suffices in the case of frost- 
bitten plants. 



n6 Principles of Plant Culture. 

Aside from the death o\' tender plants by cold, more or 
loss hardy species sutler injury in a variety of ways, of 
which the following are examples: 

\\)'*. Destruction of Terminal Buds by Cold. In 
plants which do not mature their terminal buds in autumn, 
as the raspberry, sumac, grape, etc., destruction of the tips 
o( growing shoots by frost is a regular occurrence, in 
climates of severe winters. The distance which the shoots 
are killed back, depends upon the succulency of the growth, 
the coldness o( the winter, and the natural power of the plant 
to endure cold. Plants thus affected are not always to be 
regarded as tender, since they grow wild in climates of verj 
severe winters. 

1*)3. The Darkening of the Wood (black-heart) of 
certain trees, as the pear, in climates of severe winters, 
appears to be a chemical effect of the cold. It begins at the 
center of the stem, and in extreme cases, may extend clear 
to the cambium, when the bark ceases to adhere, and the 
tree or branch thus affected dies. In stone fruits, this 
trouble is often accompanied by a now of gum. If the 
coloring of the wood does not extend to the cambium, the 
tree or branch may survive, but the tirst season's growth 
thereafter is generally feeble and the fruit or the seed crop 
often tails. During the second season, health}- growth may 
be resumed, but the heart is rarely or never restored to its 
normal color. Black- heart often results from other causes 
than cold, as from bacteria that gain access to the heart- 
wood through wounds (410). 

Other chemical changes result from cold, as the sweeten- 
ing of potato tubers when chilled, the removal of astringency 
from the wild grape and persimmon, and the heightening of 
the flavor of the parsnip. 



Plants as Affected by Cold. \ i 7 

104. Tree Trunks are sometimes Split Open by 5e= 
vere Freezing, the split remaining open until the return of 
mild weather. This most often oceurs in hard- wooded, deep- 
rooted, deciduous trees as the oak. and appears to result 
from the more rapid contraction of the outer layers of the 
wood in a sadden fall of temperature. The rents are usu- 
ally overgrown by the next annual wood layer (71). 

The splitting down of the main branches of certain varie- 
ties of the apple tree appears to be favored by the expan- 
sive force of ice in narrow crotches, which retain more or 
less of snow and water. Varieties of which the branches 
leave the trunk at a wide angle are not subject to this trouble. 

105. Bark=Bursting on the trunks of young apple 
trees often occurs when freezing weather overtakes late- 
growing and hence poorly-matured wood. In severe cases, 
the bark splits longitudinally clear through the cambium 
layer, and from the ground to the lower branches; and the 
bark is loosened from the wood nearly or quite around the 
trunk. Such trees are practically ruined, but trees slightly 
injured by bark-bursting may full}' recover. 

Ikuk-bursting is usuall}* most severe on deep, rich, moist 
soil and in seasons that favor late growth, or in which 
freezing weather occurs unusually early. Late-growing 
varieties are most subject to it. Its occurrence is lessened 
by treatment that favors early maturity of the wood (200, 
201). 

100. Root=Killing of trees. When a ver}- dr}- autumn 
passes to winter without rain or snow, the surface layers of 
the soil sometimes freeze so severely as to destroy the roots 
of young trees. Root-killing is usually most serious on 
light soils, and on one-year-old, root-grafted (301), nursery 



n8 Principles of Plant Culture. 

trees, especially when grafted with short cions (386). With 
ver} r severe freezing, on bare ground, root-killing sometimes 
occurs on soil well supplied with water. The destruction 
of the roots may be complete or only partial. In the latter 
case, the tree, if of a vigorous, hardy variety, may largely 
outgrow the trouble, though complete recovery is rare. 

Treatment that prevents late growth (200, 201), or mulch- 
ing the ground about trees tends to avert root-killing. 

197. Flower=Buds are often Destroyed by Cold while 
other parts of the plant are uninjured. This frequently or- 
curs in the peach, apricot, nectarine and certain species of 
the plum in climates of rather severe winters, especially 
after the buds have been somewhat excited b} T unseasonable 
warm weather. Flower-buds thus destined are dark-col- 
ored at the center. 

198. Flowers are Especially Sensitive to Cold. 

Fruit crops are usually wholly or in part cut off if a slight 
frost occurs during bloom, and in certain fruits, as the apricot 
and some species of the plum, the blossoms sometimes ap- 
pear to be destroyed by a degree of cold that does not 
descend to the freezing point, possibly through interference 
with pollen germination (151). When the freezing is ac- 
companied with snow, however, open flowers may escape 
without harm, probabl}' owing to the slow extraction of the 
frost (190 2;). 

199. Low Plants are often Destroyed by Ice, espe- 
cialty when the ice la} T er forms in direct contact with the 
soil about them, and remains for a time after the return of 
warm weather. Snow, of which the top has formed into a 
crust of ice, sometimes acts in the same manner. Winter 
grain and strawberry plants, are often smothered in this 



During the Dormant Period. 119 

wa} 7 . Surface drainage of ground devoted to such crops is 
highly important. 

Section II. Methods of Averting Injury by Cold 
A — During the Dormant Period 
a — By Treatment of the Soil. 

200. A Dry Soil Favors Wood Maturity, while an 
abundant water supplj' retards it. Soil treatment that re- 
stricts the water supply toward the close of the growing 
period, tends, therefore, to hasten wood maturity, and thus 
to reduce damage from cold (175). Tillage should be early 
discontinued about trees liable to winter injury, and in wet 
seasons, mulching should be removed. Oats, buckwheat or 
clover, sown in the nursery or orchard in the latter part of 
summer, promotes wood maturit} T by increasing evaporation 
from the soil, and is further useful as a covering to the 
ground in winter (196). Draining heavy or wet soils pro- 
motes wood maturity by promptly removing surplus water. 

b — By Treatment of the Plant. 

201. Pinching the Terminal Buds (416) a few weeks 
before the time for leaf fall, favors wood maturity by check- 
ing growth, as does the removal of the younger leaves, in 
whicm assimilation is most active. These methods may be 
employed upon 3'oung trees, — especially nursery trees, 
which are very liable to make late growth. The early gath- 
ering of the fruit from trees of late varieties also tends to 
hasten wood maturity. 

202* Protection with Non=Conducting Materials pre- 
vents damage from cold, with many herbaceous and shrubby 
plants, in climates where the}' are not fully hardy. By cov- 



[20 Pi t es of Plant ( *uUure* 

ering suoh plants with straw or other Utter, or with the soil, 
we lesson to some extent the intensity of the oold, but — 
more important, we prevent frequent freezing and thawing 
(190c?), and in :i great measure, the heaving of the ground, 

which on heavy or wet soil is very destructive to the roots 
o( many plants. A covering of straw, loaves or other litter, 
is preferable for low, herbaceous plants, as strawberries. 

'The covering should not exceed an inch or two In thickness, 

otherwise the plants mav be smothered in warm winter 
weather, For taller plants, as the grape ami raspberry, the 
soil is usually the most convenient and satisfaetory eovor 
ing, as a litter covering tends to attract field mice, that 
often injure woody stems. To assist in bending down the 
stems, a little earth is usually removed at the base on the 
side toward which they are to be bent. Shrubs too large 
for bending down mav be inelosed in straw or similar 
material. 

203* A Northerly Exposure is generally Least Try- 
ing to Plants in winter, because it is least subject to tlnet na- 
tions in temperature. The Influence o( the sun is here less 
perceptible, and snow remains longer than upon other ex- 
posures. Conversely, a southern exposure is most trying 
tor the same reasons. The summit o\' a hill is usually less 
trying than a valley, because the eold air tends to seek the 
lower levels, especially in still weather (210). 

J(H. Wind Breaks, i e. plantings of trees intended to 
break the force of prevailing winds, act beneficially in les- 
sening damage from eold, in so far as they prevent snow 
from drifting off the soil, and mitigate the effects of drying- 
winds (190c). 



Injury from Cold During Growing Period 121 

I> — M E 

205« Planti are mnefa moi 
cold during flu >wth period than daring 

period (171). Comparative. are in- 

jured by cold in any season until I nperatnre falls be- 

low the / 1 52* I I ) ' . or when 

called "hoarfroat ocean [t ii tt erne that v. 

chiefly jst during the gi 

od. 

206« The Cause of Hoarfrost. .1 

■wit: cannot be in the least corn;. - a por- 

tion of the water escapes. If it is but half saturated, it may 
be eornpressed somewhat without a Bape of the liquid, 

but if the compression paaaet a certain limit, the water will 
begin to eacape. 

The air ii like a sponge in this, that it is capable of taking 
up a certain amount of water. But the amount of water the 
air can take up depends very much upon its temperature, 
its capacity for water increasing as the temperature ru 
and decreasing as it falls. 

Now suppose a given amount of air at a temperature of 
F. has taken up all the it can hold at that tem- 

perature. It .-. from what has just be I. that 

if the temperature of this air is reduced, some of it-. 
will have to be set free. If the air were only half saturated 
at 50'- ]•' nperature could be reduced considerably 

bef< of its water would have to be set free: but when 

a certain degree of reduction is reached, the air will no 
longer be able to hold all ii r. and a part will 

in other words, will be precipitated. The cooling 



122 Principles of Plant Culture. 

the air corresponds to the compression of the sponge. Now, 
the atmosphere always contains more or less water in the 
form of watery vapor, and the temperature at which any 
portion of the atmosphere, on cooling, begins to precipi- 
tate a part of its water, is called the dew point. The tem- 
perature of the dew point will of course depend upon the 
amount of water the air contains. When the dew point is 
above the freezing point of water (32° F., 0°C), the preci- 
pitation is in the form of dew, or rain; but when it is below 
the freezing point of water, the precipitation is in the form 
of hoarfrost or snow. One more principle needs to be 
explained, and we are ready to understand 

207. How Frost may be Foretold. We know that 
sprinkling the floor of a room cools the air, even though the 
water used is no cooler than the air of the room. This is 
because the air, in absorbing waterj T vapor, absorbs heat, 
but this heat is set free again when the watery vapor is 
precipitated. A steam radiator gives out heat because the 
steam within it is condensing into water. It follows that 
when the dew point of the atmosphere is reached, a very 
considerable amount of latent heat is given off, which 
checks the fall of temperature. The temperature of still air, 
therefore, rarely falls much beloio the dew point, and since the 
latter depends at any given temperature upon the amount 
of moisture in the air, if we have an instrument capable of 
indicating both the temperature and the moisture of the air,, 
we may compute the lowest temperature to which the atmos- 
phere will be likel} 7 to descend during any given night. 

208t The Sling Psychrometer (psy-chrom'-e-ter) en- 
ables us to do this. This instrument consists of two thermom- 
eters, known to be accurately graduated, attached to a board 



Injury from Cold During Growing- Period. 123 



@L 



or case (Fig. 59). The bulb of one thermometer is inclosed 
in thin muslin, which is wet just before using the instrument, 
by dipping the bulb in rain water. By means of a string 
attached to the board or case, at the end 
opposite the bulbs, the instrument is 
whirled about in the air a few times, after 
which the thermometers are quickly read 
and the difference in the readings noted. 
When the air is comparatively dry, evapo- 
ration from the muslin proceeds rapidly, 
and, on account of the heat absorbed, the 
wet bulb indicates a lower temperature 
than the dry one. When the air is damp, 
evaporation is slower, and the difference 
between the readings of the two thermom- 
eters is less. In saturated air, evaporation 
ceases and the two thermometers read 
alike. By means of the following table, 
the dew point for any ordinary out-door 
temperature and atmospheric humidity may be readily 
determined. 











tTv" 














it 




¥ 




MIL 




7I> 




r 




"" 




r 




•10 




lr 




H 




I u 




70 


1 


III' 




u 




' III r 








Jjv 




;<i 




III " 








llr 



















Fig. 59. Sling psy- 
chroineter, used to 
foretell frost. 



Dry 
Bulb 



Table for computing the Dew Point in Degrees Fahrenheit. 
Wet Bulb Depression. 



10 11 12 13 



3(3 32 30 27 24 21 18 13 + 8 —1—12 —32 



37 34 32 29 25 21 19 15 9 

38 35 33 30 26 23 19 17 11 
30 36 34 31 28 24 20 16 14 

40 37 35 32 29 26 22 18 12 

41 39 36 33 30 27 23 19 14 

42 40 37 34 31 28 25 21 16 

43 41 38 35 33 30 26 22 18 

44 42 39 37 34 31 27 24 20 

45 43 40 38 35 32 29 25 21 



+ 3 — 7 —23 
+ 6 — 3 —16 

8 0—11 —31 
10 + 3—6 —22 
8 + 6—2 —15 
10 + 3—2—9 
13 + 6—3—5 
15 9—1 —12 
17 11+4—7 



—29 
—20 
—13 

—27 



J -4 



Principles of Plant Culture. 



Bui b 



Wkt Bui i« Depression. 



L 2 3 4 5 6 7 8 



9 10 11 12 13 



4<> 44 41 39 36 33 30 27 

47 45 48 40 37 35 32 28 

4S l<; 4 1 41 39 36 33 30 

4t> 47 45 42 40 37 34 31 

50 is 46 43 41 38 36 33 

51 49 47 45 42 40 37 34 

52 50 48 46 43 41 38 35 

53 51 49 47 44 42 40 37 

54 52 50 48 4(5 43 41 38 

55 58 51 49 47 45 42 39 
50 54 52 50 48 40 43 41 



57 



12 



23 


L9 


14 


+ 7 


— 2 


— IS 


25 


21 


16 


10 


+ 2 


—11 


26 


22 


18 


12 


+ 5 


— 6 


28 


24 


20 


L5 


+ 8 


— 1 


29 


26 


22 


17 


11 


+ 3 


31 


27 


23 


19 


18 


(i 


32 


29 


25 


21 


16 


9 


:;i 


30 


27 


23 


18 


12 


35 


32 


28 


\\\ 


20 


15 


36 


33 


30 


26 


22 


17 


38 


35 


32 


28 


24 


19 


39 


86 


33 


30 


26 


22 


41 


38 


85 


31 


28 


21 


42 


39 


36 


33 


29 


26 


43 


41 


38 


35 


31 


28 


45 


42 


39 


36 


33 


29 


46 


43 


41 


38 


35 


31 



55 53 51 49 47 45 

58 56 54 52 50 48 46 4:; 

59 57 55 53 51 49 47 45 
GO 58 56 54 52 50 48 46 
4*1 59 57 56 54 52 49 47 
<>2 60 58 57 55 53 51 4S 

209, To Compute the Dew Point. Find the wet bulb 
depression, by subtracting the wet bulb reading from that 
of the dry bulb, and locate this in the top line of the table. 
Next, find the dry bulb reading in the left hand vertical 
column. Opposite this, in the column headed with the num- 
ber indicating the wet bulb depression, is the dew point 

sought. 

Example: Dry bulb reading. . . . 47° 

Wet bulb « ... ._40^ 

Wet bulb depression. 7° 

Opposite 47°, in the left hand column, and under 7 in the 
top line, we find 28°, — the dew point. With these readings, 
toward sunset on a clear, still evening, we should expect 
frost, because the dew point is 4 degrees below the freezing 
point of water. A slight wind, a hazy atmosphere, or a few 
fleecy clouds would render the frost doubtful. With a dry 
bulb reading of 4.V\ and a dew point of 25°, a killing frost 
might be expected. 



hi jury from Cold During Growing Period. 125 

210. Cold Air Drainage. Warm air, being Lighter 
than cold air, tends to rise, while the colder air tends to fall. 
In a still atmosphere, therefore, the colder air accumula 

in the lowest places, which explains the familiar fact that 
hollows and rallies are colder in still weather than ridges 
and mountains. In u falling temperature and in the absence 
of wind, gentle currents of the colder air tend to follow the 
natural water courses. This explains why frost so often 
" goes in streaks. '' 

211. Wind Tends to Avert Frost because it prevents 
the settling of tin; colder air, and thus keeps the tempera- 
ture of tin; lower strata of the atmosphere nearly uniform. 

2 I '1. Clouds, Haze and Smoke Tend to Avert Frost 
because they act to some extent like a blanket, in prevent- 
ing the radiation of heat from the earth and thus check the 
fall in temperature (-17). 

213. The Proximity of a Body of Water Tends to 
Avert Frost because the water cools off slower than the air, 
and thus checks the fall in temperature of the atmosphere 
in the vicinity; also because it keeps the neighboring at- 
mosphere moist and thus raises the temperature of its dew 
point (206). The proximity of buildings and trees tends to 
avert frost, probably because these objects give up their 
heat gradually, and thus temper the surrounding atmosphere. 

214. The Localities Most Subject to Untimely 
Frosts are narrow and deep vallies that are inclosed on all 
sides, and inclined vallies that serve as channels through 
which cold air flows to lower levels. Partially cleared dis- 
tricts usually suffer more from frosts than those fully cleared, 
because the remaining forests obstruct the air drainage. 



126 Principles of Plant Culture. 

Marsh areas are subject to frost, because, in addition to 
their low situation, as compared with the surrounding land, 
their luxuriant vegetation, by exposing a large radiating 
surface, and promoting abundant evaporation, tends to cool 
the atmosphere in the vicinity. 

Valleys surrounding elevated lakes that have an outlet 
through which the colder air may flow to lower regions are 
particularly free from damaging frosts. The valley of 
Keuka lake, in west central New York, so famous for its 
vineyards, is of this class. 

215. Thermal Belts. In some elevated districts of 
mountainous regions, localities of greater or less extent are 
found in which damaging frosts are almost unknown. These 
have been called u thermal belts " and their freedom from 
frost is explained by the merging of the warm air that rises 
from the lower vallies, and is somewhat rarified by heat, 
with the atmosphere of the more elevated region, that is 
rarified to an equal extent by the high altitude. Thus the 
warm air ceases to rise, but lends its heat to temper the 
climate of the adjacent mountains. 

216. Liability to Damaging Frost Depends Com= 
paratively Little upon Latitude. Within the tropics are 
areas where frost is unknown because the temperature never 
falls to the freezing point. But in localities subject to frost, 
the liability of damage to vegetation from this cause is gov- 
erned more by cold air drainage (210) and proximity to water 
than by latitude. It is as important to select locations for 
peach growing with reference to spring frosts, in the Caro- 
•linas as in the peach belt of Michigan, and favorable loca- 
tions for the apple in Wisconsin sometimes escape damage 
from spring frosts in seasons when the apple crop is cut off 
from extensive regions of the southern states from this cause. 



Plants as Affected by Excessive Water. 127 

217. Methods of Preventing Injury by Frost. Any 

nonconducting material, lying between the earth and space, 
whether spread directl}- upon the earth or at a considerable 
height above it, acts as a blanket to intercept the radiating 
heat, and' thus prevents in a measure the cooling of objects 
beneath it. For this reason, straw, muslin, or other noncon- 
ducting material, spread over plants, protects them from 
frost. 

But while it is easj' to protect a few plants from frost b}~ 
covering them directly, it is much more difficult to protect 
large plantations in this manner. Considerable plantings 
of the strawberry have been successfully protected from 
frost b}' covering the rows in the evening with straw or 
marsh hay, and where these materials are convenient, the 
work ma}' often be cheapry and quickly performed. 

Attempts to prevent frost b} T the heat of fires, or hx burn- 
ing material that produces much smoke or vapor, have not 
been sufficiently successful to commend these methods for 
general application. 

Section II. The Plant As Affected By Unfavorable 

Water Supply 

A — By excessive water 

2 IS. Excessive Water in the Soil Destroys the 
Roots of plants. We saw (90), that oxygen is necessaiy to 
the life of roots. When the soil cavities are filled with 
water, the roots are soon deprived of ox3 x gen, because the 
little ox^-gen contained in the water is soon exhausted (91). 
Smothering and decay of the roots follow. Seeds planted 
under such conditions usually fail. The soil water that is 
most useful to land plants is that which remains attached to 



1 28 Principles of Plant Culture. 

the earthy particles after percolation* baa Dearly ceased, 
(capillary water), Such water is well aerated beoause it is 
interspersed with cavities that are filled with air. In the 

open ground, the remedy lor excessive soil water may usually 

In 1 found iu underground drainage. But the same trouble 

often OCOUrS ill polled plants, as the result, of too compact 

soil or too copious watering. The expert recognizes this 

condition by a sour odor of the soil, by lifting the pot, or 
by tapping the pot with his knuckle. If tin' soil is soggy, 

the weight will betray the fact, or the sound given out by 

the pot will be that Of a compact mass, instead of a more or 
less hollow body, as is the case with a pot, of well -aerated 
soil. To remedy the evil, repot the plant in fresh soil, of a 

proper condition of moisture, providing abundant drainage 

at the bottom of the pot, ( I L2). 

219. Injudicious Watering is perhaps the most com- 
mon cause of failure in growing potted plants. The amateur 

too often assumes that the chief need of fin 1 plants is 

frequent watering, and so gives water, in spoonful doses, as 
the surface soil of the pot appears dry, without observing 
the state of the soil beneath. The roots of the plants, in 
the meantime, may be smothering in water logged soil, or 

starving from drought if, owing to inexperience, the con- 
dition of the soil cannot be determined by the means above 
noted, the soil may be tipped out upon the hand without 
materially disturbing the roots of the plant, by reversing 
the pot and gently striking its rim on the edge of the bench 
or table. The real condition can then be readily determined. 

220. Rapidly-Growing Plants Require More Water, 

and are less liable to sutler from over-watering, than slower- 
growing ones. During the rest period (173), plants should 
be given very little water. 



/'Lints (is Affected by Excessive Water. 129 

221. Copious Waterings ;it Considerable Intervals 
are Preferable to frequent slight waterings, [t should 
Qever be forgotten that ui r is us essential as water to the 

well-being of roots (90), and that the soil, however porous, 
requires occasional ventilation (94). A considerable quan- 
tity of water, poured upon the surface; soil of a potted plant, 

in passing downward, not only thoroughly moistens the soil 
particles, but acts like a piston, forcing the vitiated air of 
the soil cavities ahead of it, and out through the drainage 

hole at the bottom of the pot, while fresh air enters from 

above as the surplus water passes out beneath. 

222. Some Species Require More Water than Others. 
The native habitat of the plant is a partial guide to the 
amount of water needed. Plants native to arid regions, as 
the cacti, and those from treeless, rocky locations, require 
little water, and are readily destroyed by over-watering. 
"Plants with narrow and tough leaves, especially when tin; 
leaf blade is vertically placed, do not, as a rule, lite much 
water; plants with broad, leathery leaves prefer a damp 
atmosphere to great moisture at the roots. Succulent plants 
with hard epidermal cells (leafless Euphorbias, succulent 
Composites, Aloes and Agaves), and thin leaved plants with 
a strong wooly covering of hairs are further examples of 
plants which require very little water".! 

223i Excessive Watering sometimes Produces a 
Dropsical Condition (oedema) in the leaves of plants under 
glass. This is most likely to occur in winter, when sunlight 
is deficient, especially if the soil is kept nearly or quite as 
warm as the air. Water accumulates in the cells, abnor- 
mally distending their walls — sometimes even to bursting. 

t Soraurer, Phyhiology of I'lants, p. 207. 



130 Principles of Plant Culture. 

An unnatural curling of the leaves, with yellow spots and 
small wart-like excrescences on their surface, are some of 
the symptoms of this trouble. Less water, increased light 
and reduced bottom heat furnish the remedy. 

*ll\. Water=Sprouts (sap-sprouts, gormands) on fruit 
trees are sometimes due to an excess of water in the soil. 
These thick, rapidly-growing shoots, with remote leaves and 
poorly-developed buds, growing from the main branches of 
unthrifty fruit trees, are most common on undrained, heavy 
soils. The}' rarely produce much fruit, but tend to rob the 
bearing branches of light and nourishment. They usually 
continue growth late, and in severe winters are often injured 
by cold. Water-sprouts may also result from over-pruning 
and from injury of the tree by cold, but in the absence of 
these conditions, they suggest the need of drainage. 

225, Fruits and Vegetables often Crack from Exces= 
sive Moisture, either through increased absorption by the 
roots, or by direct absorption through the skin. Cracking 
is most frequent after heavy rains following drought. Ap- 
ples, tomatoes, melons, carrots, kohl-rabi and the potato 
tuber are subject to it. On wet soils, draining may largely 
reined}- the evil. The selection of varieties least subject to 
it is also helpful, especially in melons and tomatoes which 
often crack in comparatively dry weather. In these cases, 
the cracking is probably due to an unequal maturing of the 
fruit which causes certain parts to grow faster than others. 

*2'2(>. Knobby Potatoes are caused by a wet period, 
following a drought, during the ripening season. Parts of 
the plant that are still alive, stimulated by abundant water, 
resume growth. But since cell division is possible only in 
the parts containing protoplasm, the mature cells of the 



Plants as Affected by Insufficient Water. 131 

tuber can no longer divide, hence growth is limited to the 
} r ounger parts, i. e., the vicinity of the buds or e} T es, and 
these therefore grow out into unshapely protuberances. 
The formation of the knob consumes a part of the starch 
previously stored in the tuber from which it grows, hence 
knobby potatoes are poorer in food value than smooth 
ones of the same lot. 

Certain varieties of potato are more disposed to knobbi- 
ness than others. In varieties normally free from it, the 
planting of knobb}* seed tubers probably does not tend to 
increase the inclination to knobbiness. 

227. Excessive Moisture in the Air is Injurious to 

plants, since it tends to hinder normal transpiration (75), 
and favors the growth of certain fungous parasites (321). 
In the greenhouse, we control the atmospheric moisture by 
ventilation and the use of water. Out of doors, we guard 
against excessive moisture in the air by giving plants suf- 
ficient room to favor the circulation of air between them. 
The latter precaution is especially important in orchard 
planting, since several fungi that pre}* upon fruit trees, as 
the apple scab (328) and pear blight (323), flourish in a damp 
atmosphere. 

B — The Plant as Affected by Insufficient Water 

228. Insufficient Moisture, in the Air, Causes Exces= 
sive Transpiration (75), which reduces the tension of the 
cell-walls and thus retards growth (63). It also tends to 
clog the leaves with useless mineral matters, causing their 
premature death, and favors the development of certain 
fungous parasites. The effects of insufficient moisture in 
the air are often very noticeable upon plants kept in living 



1 32 Principles of Plant ( 'ulture. 

rooms in winter. Suoh plants, especially when few in num- 
ber, rarely make satisfactory growth and the lower leaves 
continually perish, Moistening the air by evaporating water 

in t ho room, or Betting the pots containing the plants upon 
a table, covered with sand that is kept moist usually rem- 
edies the trouble. 

Insufficient moisture in the open air rarely occurs unless 
there is also a dearth o\' water in the soil. 

'2*20. Insufficient Moisture in the Soil Retards 

Growth both by reducing the tension o\' the cell-walls (('>;*>), 
ami by lessening the supply of food from the soil. The 
tendency of drought is, therefore, to starve the plant. 

A moderate degree of drought probably tends to promote 
flowering by restricting growth (135 1>), but if the drought 
is sufficiently severe, or sufficiently prolonged, diminution 
or failure of seedage results. 

Plants that have been subjected to insufficient water sup- 
ply from the beginning usually sutler less from drought 
than those previously well supplied with water, because 
their root system has become more extensively developed 
(112). 

~'M). Drought tends to Hasten Maturity, especially 
in annual plants, since it favors flowering (135). Lettuce, 
spinach, rhubarb etc., "run to seed" earlier if insutlicientl}' 
supplied with water. Potatoes usually ripen earlier, and 
yield less, in dry than in wet seasons. 

231. Toughness of Plant Tissues Results from 
Drought. The crispness and tenderness that give quality 
to salad vegetables, as celery, lettuce, radish etc., due to a 
distended condition of their cell-walls, is largely wanting 
when the water supply during growth has been insufficient. 



Plants as Affected by Insufficient Water. 133 

Insufficient water during growth injures the quality of 
tobacco. Leaves thus affected have a peculiar spotted ap- 
pearance when cured, and do not "sweat " properly. 

232. Crumbling <A the Surface Soil (cultivation) 
tends to Prevent Drought, since it greatly lessens the 
points of contact in the soil particles, and thus interferes 
with the rise of the soil water to the surface through capil- 
lary attraction. An air-dry surface layer of crumbled soil 
also tends to prevent evaporation by keeping the soil be- 
neath cooler. Since evaporation of the soil water occurs 
almost exclusively at the surface of the ground, cultivation 
aids materially in conserving moisture for the use of plants. 
A puddled crust on the surface of the soil, as is formed 
by rain on soils containing clay, tends, on the other hand, 
to restore capillary action, and thus to promote evaporation. 
Some very thorough gardeners cultivate all their hoed crops 
as soon as possible after rains for the main purpose of break- 
ing this crust, and thus stopping the capillar action. 

Cultivation is also beneficial b} r aerating the soil (91). 

The roots of plants should never be forgotten nor ignored 
in cultivating crops. 

*l\\\\. Mulching tends to Prevent Drought by inter- 
posing a layer of poor-conducting material between the 
ground and the sun's rays. This keeps the surface soil 
cooler and so checks evaporation. 

The best mulching material is the one that conducts both 
heat and moisture slowest. Straw, marsh hay, leaves, ma- 
nure, shavings, sawdust, spent tan and sand are all useful 
for mulching, but the first four named are generally prefer- 
able to the others, especially if free from weed seeds. 

'V'W. Irrigation, i. e., the extensive watering of out- 
door plants, is the final remedy for drought. It is a neces- 



J 34 



Principles of Plant Culture. 



sity to plant culture in arid regions, and may be profitably 
employed at certain times in the great majority of seasons, 
in very many localities where the annual rainfall would 
satisfy the needs of crops, were it more uniformly distributed. 

235. Drying, beyond a certain limit, Kills Plant Tis= 
sues by destroying, in part, their power for conducting 
water. Care must always be used to retain the normal 
moisture in buds (394), cuttings (358), and cions (386) and 
in the roots of plants lifted for transplanting. 

Section III. The Plant as Affected by Unfavorable 

Light 

A — By Excessive Light 

236. The U n o b= 
structed Rays of the 
Sun are often Injurious 
to young seedlings, to un- 
rooted cuttings and to 
plants recently trans- 
planted. It is difficult to 
separate the influences of 
light, and heat, since the 

heat is usually greatest FlG ' 60 - Lath screen used for shading cold- 
J D frames, and tender plants in the open ground. 

where the sun's rays are (After Bailey). 
brightest; but bright light 
probably stimulates 
transpiration (75), inde- 
pendent of heat, and thus 
tends to exhaust the plant 
of water. Various devices FlG 61 Shed screen built of three-inch 
are used to break the force wide slat8 > for shadin s tender P lants and for 

storing pots and boxes of slow-germinating 

of the solar rays. In out- see ds. (After Bailey). 





Plants as Affected by Light. 



135 



door culture, screens of lath (Figs. 60, 61), cloth or brush (Fig. 
62) are often placed over beds containing cuttings or tender 



iik. ,~\ 




Fig. 62. Brush screen, for shading tender plants in the open ground. (After 
Bailey). 

seedlings, as of many cone-bearing trees. Cuttings in the 
nursery are readily shaded by supporting a board over the 
row, on short stakes (Fig. 63), so as to protect them during 
the warmer hours of the da} T . Shingles, flower-pots or large 
green leaves, as of the burdock, are useful for shading plants 
of the cabbage, tomato etc. 




Fig. 63. Board shade for recently set plants, or for cuttings not yet rooted. 

In culture under glass, the glass itself is very often thinly 
washed with lime or clay to render it partially opaque, or 
lath screens are used either above or below the glass. On 
greenhouse benches, sheets of thin paper, or light cloth 
screens, are useful for shading cuttings, recently planted 
seedlings and germinating seeds. 

Shading should, never be so put on as to prevent a free 
circulation of air about the plants. 

A shade that obstructs only a part of the rays of sun- 
light at a time, as does the lath or brush screen, is gen- 



136 Principles of Plant Culture. 

orally preferable to one that continuous^ breaks the force 
of all the rays, as does paper or whitewashed glass. 

237. Cauliflower Heads should be Sheltered from 
Sunlight to prevent the formation of chloroplryll in their 
cells, which darkens their color, and gives them a strong 
flavor. The leaves surrounding the head may be tied about 
it, or broken over so as to shade the head from the direct 
sunlight. 



's j 



B — The Plant as Affected by Insufficient Light 

238. Insufficient Light is a Very Frequent Cause 
of Abnormal Development in plants. Some of its more 
conspicuous effects are 

a — Excessive elongation of the cells of the internodes, 
causing the plants to " draw up " or grow spindling. 

b — Deficient formation of chlorophyll (58), giving the 
foliage a pale-green, } T ellowish or whitish tint, and result- 
ing in 

c — Lessened assimilation, causing reduced leaf develop- 
ment and deficient vascular bundles (68). 

d — Reduced transpiration tending to watery, weak-celled 
growth. 

e — Weakening of the color and flavor of some fruits, as 
the apple and strawbeny. 

Owing to these causes, plants grown in deficient light have 
tall, slender and weak stems, few and small leaves and 
scanty roots. Such plants, though of species that normally 
grow upright, are often unable to stand erect without sup- 
port. Familiar examples are cabbage and tomato plants 
that lop over when planted out, because grown in the seed- 
box to transplanting size without " pricking off" (106); and 



Plants as Affected by Insufficient Light. 137 

grain sown too thickly on rich ground, that falls (lodges) 
before maturity. 

239. Too Close Planting Causes Deficient Light 

and all the resulting evils. Indian corn grown too thickly 
does not ear well, and is lacking in nutritive qualities; 
strawberry plants grown too closely do not fruit well, and 
the fruit lacks flavor and firmness; nursery trees grown too 
closely are slender-stemmed, deficient in foliage and have 
poorly-developed roots. A rule to govern distance in plant- 
ing has already been given (123). 

When a slender and flexible growth is desired, as in trees 
grown for hoop poles, or willows for wicker-work and tying, 
a certain amount of crowding is advisable. 

'240. Weeds Cause Deficient Light in low-growing 
crops as strawberries, dwarf beans, potatoes etc., and also 
tend to rob the plants of food and moisture. They are, 
therefore, directly injurious. 

241. Plants Under Glass are Especially Liable to 
Suffer from Deficient Light, because the walls and sash 
bars of the structure necessarily intercept a considerable 
part of the solar rays. The roofs of glass houses should be 
formed of large lights of glass, with the smallest possible 
sash bars, and the benches should be arranged to bring the 
plants as near to the glass as possible. 

242. The Electric Arc Light has been found useful 
as a supplement to the scanty sunlight of short, early-winter 
days, in forcing certain vegetables and flowers. 

243. Insufficient Pruning Prevents the formation of 

Fruit=Buds in orchard trees, by restricting light and thus 
9 



:S 



Principles of Plant Culture. 



reducing assimilation (59). Compare Fig. 64, which shows 
a fruit branch of the apple tree grown where exposed to 
abundant sunlight, with Fig. 65, showing 
one grown in partial shade.* 

244. Blanching of certain vege- 
tables, as celery, endive, cardoon and 
sea kale is practiced by gardeners to 
render them more tender and delicate. 
It is effected by excluding the light from 
the parts desired for use, until the 
chlorophyll mostly disappears. Bank- 
ing the plants with earth, or inclosing 
them in paper or in drain-tile, accom- 
plishes the end. Very close planting is 
sometimes practiced to promote blanch- 
ing. 

Section IV. The Plant as Affected 
by Unfavorable Wind 

A — By Excessive Wind 

245. Damage to trees and other 
plants by excessive wind is very familiar, 
and needs but brief notice, except to 
suggest preventive measures. 

a — The premature blowing off of fruits 
may be in a measure prevented b} T 
planting fruit trees where they are more 
or less sheltered from prevailing winds 
b}' shade trees, buildings, forests or ele- 
vations of land. Orchards may be in 
part protected b} T planting a wind-break buds. (After Kinney) 
(204) on the windward side. 




Fig. 64. 



Fig. 65. 



Fig. 64. Fruit branch of 
apple grown in abundant 
light. 

Fig. 65. Another grown 
in partial shade. 

F, fruit-buds; L, leaf- 



* See Bulletin No. 37, Rhode Island Agricultural Experiment Station. 



Plants as Affected by Insufficient Wind. 139 

b — Shade trees in exposed situations should be headed low, 
and the head should be formed of numerous branches. The 
higher the head, the more it is exposed to the wind and the 
greater is the leverage upon the trunk; several small 
branches are better able to bear the tempest than a very few 
larger ones. 

Shade trees for exposed situations should be of species 
not likely to be deformed by wind. Certain trees, as the 
white maple,* often develop one-sided if planted where ex- 
posed to prevailing winds, while others, as the sugar maple,f 
and Norwa}^ maplet are not thus inclined. 

B — The Plant as Affected by Insufficient Wind 

246. Insufficient Wind Promotes the development of 
certain Fungous Parasites (321), by favoring an exces- 
sively moist atmosphere. Orchards too closely planted, or 
surrounded by wind barriers, suffer more from fungous at- 
tacks than those having freer circulation of air between the 
trees. 

247. Insufficient Wind Promotes Damage from 
Frost by permitting the colder air to settle in the lower 
places (210). 

On these accounts, gardens and fruit plantations should 
not be entirely surrounded by wind barriers. 

248. Pollination is Dependent upon Wind in many 
plants as the coniferous trees, oaks, elms, birches and sedges; 
but as the pollen of such plants is very light, it is doubtful 
if their fruitfulness is often much restricted by insufficient 
wind. 



* Acer dasycarpum. f Acer saccharinum. % Acer platanoides. 



140 Principles of Plant Culture. 

Section V. The Plant as Affected by Unfavorable 

Food Supply 

A — By Excessive Food 

249. We saw (62) that water is the most important con- 
stituent of plant food, and we have already considered (Sec- 
tion III) the plant as affected by water supply. But a 
proper supply of the other essential food constituents is only 
second in importance to that of water. 

Excessive food is not the extreme that we have most to 
fear, since natural soils are very rarely excessively fertile, 
and we can only make them so by costly methods. Indeed, 
nearly all the constituents of plant food may be present in 
excess of the plant's requirements without working harm, 
Nitrogen, however, which, aside from water, is the most 
potent food constituent, must be used with some discretion. 

250. Excessive Nitrogen Stimulates Growth at the 

expense of flowers, seed and fruit. In crops grown for these 
parts, therefore, fertilizers rich in nitrogen must be used 
with caution. Apple, pear and quince orchards, liberally 
manured with such fertilizers, produce an excessive, over- 
succulent growth of wood, that is subject to blight and 
winter injury, and forms comparatively few fruit buds. 
Grain under similar conditions forms long, weak straw, 
with poorly-filled heads. Grape vines on over-manured 
ground produce excessive wood with few and late-ripening 
bunches. 

There is little danger of over-manuring, however, with crops 
grown for parts other than fruit or seed, so long as stable 
manures are used. But the more concentrated animal ma- 
nures, as those from poultry and the hog; the chemical 



Plants as A fee ted by Insufficient Food. 141 

compounds of nitrogen, as nitrate of soda and sulfate of 
ammonia (262); and the so-called "high-grade " commercial 
fertilizers must be used with some caution, for if applied in 
excess they may destroy the plants. 

B — The Plant as Affected by Insufficient Food 

251. It is difficult to separate the effects of a lack of 

food from those of a lack of water, since the food is mainly 

* 
conveyed to the plant in the soil water (62). But even with 

a proper water supplv, if one or more of the requisite food 
materials (61) is lacking, a normal plant structure cannot 
be built up. An excess of one food substance cannot compen- 
sate/or the lack of another, except in a few instances. 

252. Insufficient Food Dwarfs the Plant in all its 

parts. A dwarfing of the size of the plant body may occur, 
however, without a dwarfing of the seed product; hence plants 
may often bear their maximum amount of seed or fruit with- 
out attaining their maximum dimensions. Plants grown for 
seed or fruit are, therefore, less likely to be restricted in 
yield by insufficient food than those grown for their leaves, 
stems, roots or tubers. The cereals, for example, produce 
well on land not sufficiently fertile to yield equally good 
crops of tobacco, cabbage, celery, lettuce or potatoes. But 
with a sufficient restriction of food, the seed product will 
suffer diminution, or be wholly cut off. 

253. Crop-Growing Tends to Reduce Plant Food in 

the soil in proportion as the crops are removed from the 
land, and are not returned to it, directty or in equivalent. 
Fortunately, a very considerable amount of plant food is 
constantly being liberated by the disintegration and decay 
of rock or soil materials, or is being deposited from the at- 



142 Principles of Plant Culture. 

mosphere in rain and snow, so that it is impossible to ex- 
haust the soil of plant food, even with the most improvident 
culture. But the cultivator should aim at the largest returns 
from his soil, and these are impossible without restoring cer- 
tain materials that continued crop removal invariably re- 
duces below the limit of profitable } T ields. 

254. The Food Elements Most Likely to be Defi= 
cient, when plants are property supplied with water, are 
nitrogen, phosphorus and potassium. These are all liberated, 
in greater or less quantities, when vegetable and animal 
material (organic matter) decays in the soil; hence all such 
material has more or less value as fertilizers. But we need 
not wholly depend upon refuse organic matter for fertilizers, 
since the leguminous plants add nitrogen to the soil (260), 
and compounds of nitrogen, phosphorus and potassium can 
often be purchased in artificial fertilizers at prices that place 
them within the reach of the cultivator. 

255. Nitrogen is the Most Important Fertilizing 
Element to the cultivator, because it is liberated in small- 
est amount by rock decay, and is most expensive in the 
market. Nitrogen is chiefly used by plants in the form of 
nitrates, i. e., in combination with certain other substances 
as potash, lime, soda, magnesia and iron. Ammonia, which 
is a gaseous compound of nitrogen and hydrogen, is also 
used to some extent by plants. Free nitrogen, the most 
abundant constituent of the air, plays no direct part in 
plant nutrition. 

256. The Sources of Nitrates in the Soil are 

a — Nitrification (nit-ri-fi-ca'-tion), 03^ which the nitrogen 
contained by organic matter in the soil is changed to nitric 
acid, through the agency of microscopic plants (bacteria). 



Plants as Affected by Insufficient Food. 143 

The nitric acid thus formed combines with certain sub- 
stances (bases) in the soil, as potash and lime, forming 
nitrates (255). 

b — Symbiosis (sym-bi-o'-sis) on the roots of leguminous 
crops, through which atmospheric nitrogen is changed to 
nitric acid. 

c — Deposits from the atmosphere in rain or snow. 

d — Ammonium salts or nitrates applied directly to the soil. 

257. The Conditions Affecting Nitrification are 

similar to those affecting plant life in general, since nitrifica- 
tion results from plant life. As it takes place below the 
surface of the soil, it is favored by the same conditions that 
favor the root growth of land plants, viz., aeration, warmth 
and moisture. In general, it is active during the growing 
season, but at a standstill during the dormant period. It 
does not proceed rapidly in spring until the soil has become 
sufficiently warm to promote active root growth. 

Nitrification also releases the other food materials con- 
tained by organic matter. 

258. Soil Aeration Promotes Fertility by favoring 
nitrification. Thus cultivation, and drainage (of heavy soils) 
not only directly promote the growth of plants by assisting 
aeration (94), but they actually increase plant food. Early 
plowing in spring promotes nitrification by favoring warm- 
ing of the soil. Cultivation in dry weather further pro- 
motes plant nutrition by preventing the accumulation of 
soluble plant food in the dry surface soil, where it is de- 
posited by evaporation above the reach of roots. 

259. Partially Decomposed Organic Manures Act 
More Promptly than fresh ones, because nitrification has 
already commenced in these materials. 



144. Principles of Plant Culture. 

260. Leguminous Plants Enrich the Soil with nitric 
acid (256), which is formed from atmospheric nitrogen in the 
tubercles on their roots through the agency of microscopic 
plants (113). Even when a part of these crops is removed 
from the land, as when clover is harvested for hay, or peas 
for their seed, the land remains richer in nitrogen than be- 
fore the crop was planted. The principal leguminous crops 
are the clovers, peas, beans, lentils, sanfoin, vetches, alfalfa, 
lupine and certain species of Lathyrus. Highly valuable as 
are these crops for the nitrogen they leave in the soil, it 
should be remembered that they do not contribute phos- 
phoric acid or potash, and hence must not be wholly de- 
pended upon for soil fertility. 

Leguminous plants are supplied with nitrogen by the 
bacteroids in their roots, and hence do not require this ele- 
ment in fertilizers. 

261. Rain and Snow Add Nitrogen to the Soil in 
small quantities, both as nitric acid and ammonia, which 
have been taken up from the air, but the amounts thus ad- 
ded, while useful to plants, are not under our control. 

262. Nitrogen may be Purchased for fertilizing pur- 
poses as sodium nitrate (nitrate of soda, Chili-saltpeter), and 
ammonium sulfate (sulfate of ammonia). The former is 
available as plant food as soon as it is dissolved in the soil 
water. It is best applied immediately before the planting 
of a crop, or in small quantities at intervals during 
growth; since it is in danger of being washed out of the soil 
in drainage water. Sodium nitrate is especially useful for 
garden crops started early in spring, when the soil is too 
cool for active nitrification (256). The surface soil is apt to be 
poor in nitrates in spring, because the}' are often washed 
down by the autumn and winter rains. 



Plants as Affected by Insufficient Food. 145 

Ammonium sulfate is mostly changed to nitrates in the 
soil before it is used by plants, and hence is less prompt 
in its action than sodium nitrate. It is more tenaciously 
held by the soil than sodium nitrate, and is therefore less 
likely to be lost by washing. 

263. Phosphorus is used by plants in the form of 
soluble phosphoric acid, which exists in the soil in combi- 
nation with lime, iron and alumina, as phosphates of these 
substances. It may be purchased in the form of mineral 
phosphate of lime, and ground bone. The former is insolu- 
ble in water unless it has been treated with strong acid, 
when it is known as acid phosphate or superphosphate. Phos- 
phoric acid is not readily washed out from the soil, even in 
its soluble form. 

264. Potassium is used 03- plants in the form of pot- 
ash, i. e., potassium combined with oxygen. Potash ex- 
ists in the soil, mainly, in combination with chlorin (chlorid 
or muriate of potash), with sulfuric acid (sulfate of potash), 
or with nitric acid (nitrate of potash). All these forms of 
potash are freely soluble in water, and are therefore imme- 
diately available as plant food. Nitrate of potash (saltpeter) 
is a most valuable fertilizing material, since it contains both 
potash and nitrogen, but unfortunately its price is too high 
to render its use for this purpose economical. The muriate 
either pure or in crude form (kainit), and sulfate may, on 
the other hand, be purchased at reasonable prices. The lat- 
ter is considered preferable for tobacco and potatoes as it is 
thought to produce a better quality of product. The muri- 
ate acts more promptly than the sulfate, however. 

265. Wood Ashes are a Valuable Fertilizer, espe- 
cially when unleached, as the} T contain both potash and 



146 Principles of Plant Culture. 

phosphoric acid. In leaching, the potash is mostly washed 
out, but the phosphoric acid is largely retained. 

266. Farm and Stable Manures should be the first 
dependence of the cultivator, but these may often be profit- 
ably supplemented b}' commercial fertilizers. Aside from 
farm and stable manures, leguminous crops are undoubtedly 
the cheapest source of nitrogen for the farm, and, with un- 
leached wood ashes, furoish all the needed fertilizing ingre- 
dients for grain crops grown in rotation. For garden crops, 
however, if sufficient stable manure can not be obtained, 
more nitrogen can often be profitably used than leguminous 
crops alone can furnish and for such, commercial fertilizers 
may often be advantageously added. 

267. Crops Suggest Their Own Needs to some ex- 
tent, so long as they are not suffering from drought. As a 
rule, a lack of nitrogen is indicated by pale-green foliage, 
or small growth of leaf or stalk. Excess of nitrogen is indi- 
cated b} T excessive growth of leaf or stalk, with imperfect 
bud-, flower- and fruit development. Lack of phosphoric 
acid is indicated by scanty crops of light or shrunken seed, 
on plants of normal size. Lack of potash is indicated by 
small crops of inferior fruit, accompanied by satisfactory 
growth. 

268. Crop Rotation Economizes Plant Food, because 
some crops use more of a given food constituent than others. 
Alternating crops having different food requirements tends 
to prevent the exhaustion of special food substances. 

269. A Growing Crop Tends to Conserve Fertility 

because it reduces drainage b} T taking up water from the 
soil, and at the same time, appropriates the available plant 
food, tlyis preventing the loss of the latter b}^ washing out. 



Plants as Affected by Parasites. 147 

270. Manures are, in part, the Raw Material from 
which the cultivator turns out valuable products. They 
should, therefore, be most carefully preserved and applied. 
Leaching of the manure pile by undue exposure to rain, 
and over-rapid fermentation, b} T which nitrogen escapes into 
the air as ammonia or other gaseous nitrogen compounds, 
should be stringently avoided. All refuse organic matter 
should, so far as possible, be made to increase the always- 
too-small stock of manure. 

Section VI. Plants as Injuriously Affected by 

Parasites 

The only instance of a beneficial plant parasite of special 
interest to the cultivator, is the bacteroids in the roots of 
leguminous plants, which we have already considered (260). 
Many parasites (2-t) of harmful insects are beneficial, but 
these are beyond our scope. We need therefore to treat 
here only those parasites that are directly injurious to 
economic plants. 

271. The Injurious Parasites of plants are Very Nu= 
merous and a scientific classification of them is quite be- 
yond the limits of the present work. We shall only en- 
deavor to arrange the different parasites into groups based 
on their manner of working injury, and the methods by 
which they may be controlled. 

With reference to the character of their injury, and the 
preventives used, as well as in their natural characteristics, 
plant parasites are readily separable into two great classes, 
viz., animal and vegetable parasites. These classes will be 
considered in their order, 



148 Principles of Plant Culture. 

A — The Plant as Affected by Animal Parasites 

a — By quadrupeds aud birds. The four-footed ani- 
mals that injure cultivated crops nearly all belong to the 
class known as rodents, which includes mice, gophers, rab- 
bits, woodchucks, moles etc. These may usually be con- 
trolled by trapping, shooting, or poisoning, or b} r protecting 
the plants. 

272. Damage from Mice to orchard and nursery trees 
is very common. Mice are usually most troublesome on 
sod ground when covered with snow, especially beneath 
snow banks, hence all grass should be removed in autumn 
from the immediate vicinity of the trees. It is well to ridge 
the soil a little, directly about the trees, so that the mice, in 
burrowing beneath the snow, will not be likely to come in 
contact with the stems. Packing the snow immediately 
about the trees is helpful when damage is discovered dur- 
ing winter. The stems of orchard trees may also be wrap- 
ped in heav3 T paper or inclosed in fine wire netting. If 
tarred paper is used, it should be promptly removed in 
spring, or it may injure the bark. 

Stored seeds of almost all kinds must be carefulty guarded 
against mice. 

273. Gophers are often troublesome in eating planted 
seeds, and in burrowing about the roots of young orchard 
trees. They may be poisoned by placing about their holes, 
corn, soaked in water containing stiychnin in solution. 

274. Rabbits are especially troublesome in nursery 
trees, when the ground is covered with snow. The most 
satisfactor} 7 protection is to inclose the nursery with a fence 
of poultry netting, which should be banked up a little at the 



Plants as Affected by Animal Parasites. 149 

bottom to prevent the rabbits from passing under. It should 
be high enough to reach above the surface of the deepest 
snow. 

Orchard trees may be protected against rabbits by inclos- 
ing the trunks with the devices mentioned under sunscald 
(186). Smearing the stems with blood has also been recom- 
mended. 

275. Woodchucks are often troublesome to growing 
crops, but as they are seldom numerous, shooting or trap- 
ping general^ suffices to prevent serious damage. Moles 
are very troublesome in some localities by eating the roots 
of plants. They may be largely controlled by trapping with 
mole-traps. 

2 7 6. Birds are often troublesome by eating unharvested 
fruits. Inclosing the trees or plants with fish netting, when 
this is practicable, is perhaps the most satisfactory prevent- 
ive. The netting msiy be purchased at a low price, and the 
same piece may be used several seasons. 

b — By insects, worms, slugs and snails. As worms, 
slugs and snails work the same kind of injuries as some 
insects, and are controllable by the same methods, we do 
not distinguish between them in the following paragraphs. 

277. Many Insects are Beneficial by destroying other 
insects, or by promoting pollination (151). We should not, 
therefore, wage indiscriminate warfare upon all insects. 

278. Methods of Preventing Insect Ravages to 
plants are various, as inclosing the plants; entrapping, re- 
pelling or removing the insects, or destroying them by 
means of insecticides. The important question, in the case 
of any injurious insect, is by which one of these methods it 
may be most effectually and cheaply controlled. 



I KO 



Plant ( "uhure, 




\! J *,). Inclosing the PlAntd i s practicable in a few oases, 
as with the striped ououmber beetle x The hills, in whioh 

^"^^a ououmber s, melons, 

\ squashes dr., are plant - 

ed, may be covered with 

I'll. 66. >, IV.MI .«>\ <tV(i t'l.UUO t\>l' |Hl>l<VtilU'. 

hills of the melon and ououmber :l frame having tme- 

meshed wire or cotton netting (Fig, 66) tacked over the 
top, whioh prevents the beetles from Injuring the plants. 

280. Trapping the insects is praotioable in i few 
oases, :i s with outworms, whioh often oonoeal themselves 
during the day beneath objects on the ground. They will 
frequently be found In numbers beneath handfuls of green 
olover, or other herbage plaosd on the ground near the 
plants whioh it is desired bo proteot By poisoning the 
herbage with Borne form o( arsenic (284), some of the out- 
worms mav be killed, but many are likely bo escape unless 
destroyed by other means, as hand picking (282). 

281. Repelling insects by means of offensive odors is 
partially effectual in somo oases, as with the squash-vine 
borer. 1 Corncobs or other objects, dipped in coal tar and 
placed among the plants, repel many of the moths that 
produce the borers. 

282. Hand Picking, I. e., removing the insects from 

the plants by hand, is the most satisfactory method tor 
destroying certain inserts, as the tobacco- or tomato worm,} 
and other large oaterpilliars, and the pose beetle.! \ vessel 
of water with a little kerosene on the surface, in whioh bo 
throw tin 4 insects as they are gathered, is a convenient way 

o\ destroying them. In some eases, the insects can be 



' 



Plants <r Affected by Animal Para itt 151 

k<:n or knocked from the plant direct! 
This method it often employed In & ng the pot 

beetle, 41 Digging ont cntwormf and irbite grubs 1 from 
about corn and strawberry plants, and cutting cut bor< 
from ij<< re often the meet effectual 

methods for destroying these in e< 

*iM>. Destroying insects by Poisons Of Caustics if 
the method m< nerally available. The material need 
called an insecticide (in sectf I cide) and if satisfacto 
must be destructive to the in irithout injuring the 

plant to irhicfa it is applied, or rendering the plant or its 
products unfit, for food. The insecticides in moat gem 

are certain compounds of arsenic (Pai n, London 

purple, white arsenic), hellebore and pyrethrum powdV 
tobacco, kero ad various compounds of soda and 

potash. With the exception of kerosene and the alkali 
compounds, all these may be ased either i powder or 

with water. 

jSJ. The Arsenical Compounds;; effectual as 

rj irben largely diluted. When applied 
in irater, however, they arc liable to injure foliage in pro 

portion to the amount of soluble arsenic they <ontain. 

When insoluble in water, they require stirring to keep them 
in suspension, 

\JS.">. Paris <"ireen (arseuite of copper), when pure 
nearly insoluble compound, and ms diluted 

at the rate of one pound to two hundred gallons of wa'' 
upon the foliage Of moat plants. For the peach and ft 
tarine it should he diluted one-half more. Pure I' en 

vithout sediment, in a'jua ammonia. 



ryphora dteemUneata. /. 



1 5 2 Principles of Plant Culture. 

286. White Arsenic (arsenious acid) is slightly solu- 
ble in water, and hence is dangerous to foliage unless used 
with care. If applied immediately after its addition to the 
water, it may be safely used upon the foliage of the apple, 
plum and cheny at the rate of one pound to fifty gallons, 
but constant stirring is required to keep it in suspension. 

287.1 London Purple (arsenite of lime, with certain 
impurities) often contains soluble arsenic, and, like white 
arsenic, must be used with caution. It ma} 7 be safely 
applied to many plants at the rate of one pound to two 
hundred gallons of water, if put on immediately after its 
addition to the liquid, but for the peach it should receive 
greater dilution. London purple is considerabty cheaper in 
the market than Paris green. 

The addition of fresh milk of lime to water to which 
white arsenic or London purple has been added largely pre- 
vents their tendency to injure foliage. 

Both Paris green and London purple, when perfectly 
mixed with 150 parts, by weight, of land paster, or an equal 
bulk of any other cheap non-poisonous powder, are effectual 
in destroying the potato beetle and many other leaf-eating 
insects (307). 

288. Compounds of Arsenic are Deadly Poisons and 
should always be handled with the greatest care. 

'2 SO. Hellebore (hel'-le-bore) Powder, i. e., the ground 
root of white hellebore* is a far less virulent poison than 
the arsenic compounds. It is therefore useful for destroy- 
ing a class of insects against which a deadly poison cannot 
wisety be used, as the imported currant worm,! and the 
cabbage caterpillar. X 

* Veratum album. f Nematus ribesii. % Pteris rapce. 



Plants as Affected by Animal Parasites. 153 

When used dry, hellebore powder may be dilated with 
once or twice its bulk of flour, which causes it to adhere 
better to the foliage than if used alone. When applied with 
water, a heaping teaspoonf ul or more may be added to three 
gallons. The dry powder is very light and should only be 
used in a still atmosphere. 

A decoction made by boiling the root of white hellebore 
in water is said to possess insecticide properties similar to 
those of the powder. 

290. Pyrethrum (py-re'-thrum) Powder, (Persian 
insect powder, Dalmatian insect powder, Buhach) is the pul- 
verized flowers of certain species of Pyrethrum.* 

Pyrethrum powder is not poisonous to the higher animals, 
but the oil that pervades it is destructive to many insects. 
As the oil is extremely volatile, pyrethrum is better adapted 
for use under glass, or with plants otherwise inclosed. It 
is not injurious to foliage or flowers. When fresh and pure, 
pyrethrum powder may be diluted half or more in bulk with 
any other light and cheap harmless powder, but the 
mixture should stand a day or two before use, to enable the 
diluent to absorb the oil. The powder ma} 7 be used with 
water at the rate of half a pound to three gallons. 

The pyrethrum plant is comparatively hardy, and has 
been successfully grown in northern United States. It is 
said that a decoction of the unopened flowers possesses the 
insecticide properties of the commercial product. 

291. Hellebore and Pyrethrum Powders should be 
Kept in Close Vessels^ since their poisonous properties are 



* " Persian insect powder " is made from the flowers of Pyrethrum roseum, and 
P. carneum; "Dalmatian insect powder "and "Buhach" are made from those of 
P. cinerai<ffolium. " Buhach " is the trade name of a pure product prepared in 
California. 
IO 



154 Principles of Plant Culture. 

volatile. In purchasing, only fresh samples should be ac- 
cepted. If fresh and pure, these powders produce a ting- 
ling sensation when applied to the nostrils. 

292. Tobacco Smoke is much used for destroying 
" lice " or " green fly " (aphidse) on plants under glass. For 
this purpose, the partially-dry stems or leaves are burned 
upon pans or bricks, or in small, sheet-iron stoves. Many 
delicate flowers are, however, injured by tobacco smoke. 

Stems or leaves of tobacco, strewn abundantly beneath 
greenhouse benches, tend to prevent the multiplication of 
aphidae. 

Several semifluid extracts of tobacco are sold which may 
be evaporated in the greenhouse, over an oil stove, or pre- 
ferably by steam under pressure. Some of these are very 
efficient for destroying insects, and do not injure flowers. 

293. A Strong Decoction of Tobacco is often used for 
destro}ing aphidae on plants in rooms where tobacco smoke 
would be objectionable. The plants are immersed in, or 
washed with the decoction. The same is often effectuall}- 
used on young plants of cabbage, cauliflower and turnip, to 
prevent their destruction by the flea beetle.* 

294. Kerosene is a very useful insecticide for a class 
of iusects not readily destroyed by other means (316). It 
has generally been used as an emulsion made with soap and 
water, for which the following formulas are good. 

a — Dissolve one quart of soft soap in two quarts of boil- 
ing water; remove from the fire, and add at once one pint 
of kerosene. Agitate violently in a closed tin can for three 
minutes or pump the mixture while still hot through a force 
pump. For use, dilute with an equal quantity of water; or 

* Phyllotreta vittata. 



Plants as Affected by Animal Parasites. 155 

b — Dissolve one-fourth pound of good, hard soap in two 
quarts of boiling water, and add at once one pint of 
kerosene. Agitate or pump, as above directed. For use, 
dilute with twice its volume of water; or 

c — Dissolve one-half pound of hard soap in one gallon 
of boiling, soft water, add at once two gallons of kerosene, 
and churn or otherwise violently agitate for five or ten 
minutes. For use, dilute with 15 parts of soft water. 

Kerosene may also be applied in intimate mixture with 
water, secured by pumping both liquids at once through a 
good spraving nozzle. About ten per cent, of kerosene 
should be used for most plants (317). 

295. Caustic Potash, in solution, is useful for des- 
troying certain scale insects, as the 0}^ster-shell bark-louse,* 
for which solutions of one-fourth pound to the gallon of 
water may be applied during winter. 

296. Resin (or rosin) Washes are valued for destroy- 
ing various scale insects in Southern and Western United 
States. They are adapted, with modifications, to both dor- 
mant and growing trees. The resin is sometimes saponified 
with caustic soda and simply diluted with water; fish oil, 
or petroleum may also be added. The following and other 
formulas are in use : 

a — Dissolve one pound of caustic soda in one gallon of 
water in a covered iron kettle. Pour out half of the solu- 
tion, and to the remainder add 8 pounds of resin, and boil 
until dissolved. Then pour in very slowly the rest of the 
caustic soda solution, and boil the whole, stirring it con- 
stant^ until it will unite with water, forming a liquid 

* Mitilaspis pomorum. 



156 Principles of Plant Culture. 

resembling milk. Dilute to 22 gallons for use. This 
mixture may be used during the growing season; or 

b — Place 30 pounds of resin, 9 pounds of 70 per cent, 
caustic soda and \\ pints of fish oil, in a closed iron kettle 
and cover with five or six inches of water. Boil until the 
liquid has a dark-brown color, after which slowly add water 
until the whole makes 100 gallons; or dilute a part of the 
liquid at this rate, keeping the remainder as a stock solution. 
This is for use in the dormant season. For use in the 
growing season, similar solutions are used with more 
dilution. 

297. Hydrocyanic Gas. Another method of destroy- 
ing scale insects used in California and the Southern States 
is to treat the tree, which is first inclosed in an oiled-cloth 
tent, with hydrocyanic gas. One ounce of cyanid of pot- 
assium and one measured ounce of sulfuric acid are placed 
in an earthen or leaden jar containing three measured 
ounces of water. The jar is covered with burlaps to pre- 
vent the rapid escape of the gas. The tent is left over the 
tree fifteen minutes to one hour. It is advisable to apply 
this treatment during the dormant season, and in a cool 
period. 

298. Fir=Tree Oil, is considerabty used for destroy- 
ing scale insects and the mealy bug * in greenhouses and 
conservatories. It is mixed with warm, soft water at the 
rate of a tablespoonful of oil to a pint, and applied with a 
syringe; or the plants are dipped into the mixture. 

299. Hot Water may also be used for destroying the 
above-named insects (298) and plant lice (aphidre). Infested 
pot-plants are inverted and immersed five or six seconds 

* Dactylopivs. 



Plants as Affected by Animal Parasites. 157 

in a vessel containing water at 120° F. This treatment 
must be used with caution. 

300. Insect Attacks Sometimes Become Formid= 
able from the vast number of the individuals. The chinch- 
bug,* the army-worm t and various species of locusts or 
grass-hoppers sometimes devastate large tracts of countoy. 
For the destruction of these insects, special means must be 
employed. 

301. The Chinch=Bug may be, in a measure, controlled 
by burning over all grass land in early spring, in seasons 
when attacks are expected. The bugs may be kept out of 
corn fields by plowing a furrow away from the corn, on the 
side from which the attack is probable, and strewing stalks 
of fresh corn in this. As the insects congregate on the corn 
in the furrow, they should be destroyed with kerosene (294). 
Persistent and thorough work is essential to success. 

302. The Army=Worm may often be prevented from 
migration b} T plowing a deep furrow, as above directed, and 
making the side toward the endangered crop vertical, with 
a spade or shovel. The insects will congregate in the fur- 
row where they may be destro} r ed by dragging a log over 
them. 

304. Grasshoppers and Locusts may be destro} T ed, 
before they have attained their wings, by drawing over the 
infested ground, a " hopper-doser " which consists of a 
shallow, sheet iron pan, with a vertical, cloth-covered back. 
The pan contains a little kerosene, and the cloth back is 
kept saturated with the same liquid. The insects jump into 
the pan, or against the cloth back, thus becoming wet with 
the kerosene, and soon perish. Grasshoppers ma} T also be 



* Bhssus leucopterus. f Leucania unipuncta. 



1^8 Principles of Plant Culture. 

poisoned by distributing bran mixed into a mash with water 
containing arsenic in solution. Plowing grass land contain- 
ing the eggs of grasshoppers tends to prevent an attack. 

304. Apparatus for Applying Insecticides. Powders 
are readily applied upon low-growing plants, as the potato, 
cabbage, etc., by means of a sifting box consisting of a pail, 
with a perforated bottom, a rigid handle and a tight-fitting* 

cover. (Fig. 67). For 
small plants, as young 
potato tops, the lower tin 
disc which has a circular 
hole in the center, is laid 
inside, on the bottom of 
the box, and held in place 
by small lugs soldered to 
the wall as shown. When 
it is desired to spread the 
powder more, the other 
disc is used. 

For taller plants, a 
powder bellows is desir- 
able. 

Liquids are best distributed with a force pump, fitted with 
a hose of a length suitable to the height of the tree or plant, 
and an atomizing nozzle (Figs. 68, 69, TO). For tall trees, 
the hose nozzle may be elevated by attaching it to the end 
of a light pole. 

Excellent bellows and force pumps, designed expressly 
for applying insecticides, are now manufactured. 

305. The Use of Insecticides. In treating any given 
insect, the most important question to decide, is the manner 




Fig. G7. Sifting box, for applying powders. 



Plants as Affected by Animal Parasites. 159 



in which it works its injury, as upon this will depend the 
preventive measures to be used. 

306. Injurious Insects are referable to Two Classes, 

viz., eating insects, i. e., those feeding directly upon the plant 

tissues, as the potato beetle, 

the apple-tree borers,* the 

plum curculio;f and the 

sucking insects, i. e., those 

feeding only upon the juices of 

the plant, as plant lice, the 

squash-bug, t the oyster-shell 

bark-louse A 





Fig. 68. Fig. 69. 

Fig. 68. A convenient and serviceable spray pump, using a common pail for a 
reservoir. 

Fig. 69. A similar pump with attachment by which kerosene and water may be 
sprayed together (294). Both are made by the Deming Co., Falem, 0. 

307. The Eating Insects, may be subdivided into leaf- 
eaters, those that devour the foliage; root-eaters, those that 

* The round-headed apple-tree borer, Saperda Candida; the flat-headed apple- 
tree borer, Chrysobothris femorata. f Conotrachelus nenuphar. % Anasa tristis. 
\ Mytilaxpis pomorum. 




160 Principles of Plant Culture. 

devour the roots; and burrowers, those that harbor within 
some parts of the plant by eating a passage for their bodies. 

308. The Leaf=Eaters include numerous species. The}' 
are readily recognized by the fact that the leaves, on which 

they feed, disappear more or less 
rapidly. The} T ma} T generally be de- 
stined by applying a poison to the 
foliage, for which purpose the arsen- 
ical compounds (284) are well adapt- 
ed. In cases where the use of a 
deadly poison is unsafe, hellebore 
(289) or pyretbrum (290) ma} r be sub- 
~">v A stituted. 

309. The Root=Eat= 
ers include fewer species 
than the leaf-eaters (308) 
and are usually more 
difficult to control. 
Carbon bisulfid, in- 
jected into 
the soil 
about the 
roots of 
cabbage 
and cauli- 
flower 
plants, with 
a n instru- 
ment devis- 



( 




Fig. 70. Steam spraying outfit, manufactured by Shipman 
Engine Co., Rochester, N. Y. 

ed for the purpose (Fig. 71), has been successfully used to 
destroy the cabbage maggot * and may be found useful in 



* Phorbia brassier. 



Plants as Affected by Animal Parasites. 161 

other cases. Attacks of this insect have also been success- 
fully prevented by surrounding the stem of the young plant 
with small cards of thin tarred paper. One of these cards, 
the tool used for cutting them, and the manner of using the 
tool are shown in Figs. 71, 72 and 73. 

310. Burrowers, as the term is 
here used, includes not only the so- 
called borers that burrow within the 
stems and roots of plants, but also 
the leaf-miners, that live between the 
surfaces of leaves, and the insects 
that pass their larval stage within 
fruits. Insects of this class are diffi- 
cult to control, since they are mostly 

beyond the reach of insecticides. 

• 

311. Borers that infest the 

„„ m ' "'.'" . . . trunks and main branches of trees, 

*ig. 71. Tool for lDjecting 

poisonous liquids about the ma}' often be kept out by appl}"ing 

roots of plants. n ■.. , ,, 

strong alkaline washes to these parts. 
Soft soap, reduced to the consistenc}' of thick paste 
by a strong solution of washing soda, applied to 
the trunk or branches forms a rather tenacious coating 
which repels the female insect. Painting the trunks of 
small apple trees a short distance above and below the sur- 
face of the ground with common paint, or pine tar, is said 
to prevent the entrance of the round-headed borer (306). 
Protecting the trunk with straw or lath, as recommended to 
prevent sun-scald (196) also tends to keep out these insects. 
Borers in the trunk may often be destroyed b}~ probing 
their holes with a flexible twig. 




162 



Principles of Plant Ctdture. 



31*2. Leaf=Miners often infest spinach and beets grown 
for greens, rendering the leaves unfit for use. For these 
insects we can offer no preventive measures of established 
value. The application of powerful odorants to the young 
foliage, as coal tar water or a solution of carbolic acid, may 
prove beneficial. 

313. The Codling=Moth,* which causes so-called 
" wormy " apples and pears, is controlled by spraying the 
trees at the time of egg deposit, with water con- 
taining Paris green (285). The first spraying 
should be given as soon as the petals (143) fall, 
to be followed b} T a second six to ten da} r s later. 
If much rain falls at this season, the sprayings 
may need frequent repetition. A drop of poison- 
ed water should be lodged in the calvx (142) of 
every fruit, and as this evaporates, the film of 
poison deposited on the skin intercepts the 
newly-hatched insect as it eats 
its wa} T inward, and kills it. 

314. The Plum Curculio 

(306) that so 
often stings 
3'oung plums, 
causing them 
to drop be- 
fore matur- 





(D 



<Z> 



Fig. 74. 



73. 



Fig. 72. 
Fig 72. Card of tarred paper, for placing about the stems of 
young cabbage and cauliflower plants. Reduced one-half. 
Fig. 73. Tool for cutting the cards. 

Fig. 74. Manner of using the tool. The dotted lines show 
lty, IS COn- the position of the edge of the tool on the paper. 

trolled b} T jarring the beetles, that deposit their eggs in the 
young fruit, upon sheet-covered frames (Fig. 74), on cool, 
still mornings while the beetles are stiff. 



The jarring should 



* Carpocapsa pomonella. 



Plants as Affected by Animal Parasites. 163 

begin almost as soon as the petals (143) fall, and will need 
to be continued every cool, still morning as long as any 
beetles are found. The work must be done in the early 
morning. An}' light wood frame, covered with cloth may 
be used as a substitute for the more convenient device 
shown in the figure. Where the substitute is used, the 
beetles must be looked for on the sheet and destroyed as 
found. 

315. The Prompt Destruction of Infested Fruits 
materially aids in keeping the fruit-burrowing insects in 
subjection. Hogs and sheep in the orchard are most valu- 
able assistants in this work. The apple-maggot* is more 
effectually controlled in this manner than by any other 
known method. 

316. Sucking Insects include man} 7 species. They 
feed on the juices of the plant which they infest, and do 

not directly devour its 
tissues, as do the eat- 
ing insects; but they 
slowly exhaust i t s 
vitality by their con- 
tinual drain upon the 

Fig. 74. Curculio catcher. It is wheeled beneath 

the branches of the tree, when the latter are struck reserve IOOQ. 1 Ue SO- 

with a light, cloth-covered mallet, which jars the G8i \\ ec \ sca \ e insects be- 
beetles upon the sheet-covered frame, from which 

they roll into the box beneath. For small trees the long to this class, 

trunk slips in through the slot at the left. These are especially 

difficult to destroy, since they are dormant the greater part 
of the year, and in this condition are protected by their 
comparatively resistant scales. 

Sucking insects are not susceptible to poisonous insect- 
icides, hence we must resort to materials that clog their 

* Try pet a pomonella. 




164 Principles of Plant Culture, 

breathing pores, as kerosene (294); that dissolve their eggs 
and scales, as potash solutions; or that form an air tight 
coating over them, as the resin washes (295).* 

317. The Life Histories of Injurious Insects, which 
cannot here be taken up, may profitably be studied by the 
plant grower. A standard work on economic entomolog}' 
will furnish the needed information. 

B — Plants as Affected by Vegetable Parasites 

318. Many of the most serious enemies of cultivated 
plants belong to this class. As a rule, vegetable parasites 
contain no chlorophyll, and hence are incapable of assimi- 
lating their own food. While most of them belong to the 
lower orders of plants, a few species are highly developed 
and produce true flowers and seeds. 

a — Flowering or Phaneroganic (phan'-er-o-ga'-mic) 
parasites. 

Of these the only ones sufficiently common or injurious 
to need mention are the broom rapes, and the dodders. 

319. The Broom Rape of Hemp and Tobacco, t is the 

most injurious species of this class. The seeds germinate 
in the soil, and the young plants attach themselves to the 
roots of their host which they enfeeble b} 7 robbing it of 
nourishment. In the case of hemp, the parasite also injures 
the quality of the fibre. 

Preventives. The seeds of hemp or tobacco should not be 
taken from a crop infected with broom rape. Infested 
fields should be planted for several years to some crop not 



* The cottony cushion scale, Icerya purchasi, which has been very destructive 
to the orange in California, has been nearly suppressed by the introduction of an 
Australian parasite, the Vedalia cardinalis. 

f Philipcea ramona. 



Plants as Affected by Fungous Parasites. 165 

attacked by broom rape, as potatoes, Indian corn, beans, 
grains or grasses. In infested crops, the broom rape should 
not be permitted to mature its seeds. 

320. The Dodder of Clover and Flax,* are most in- 
jurious of their class. The young plantlet attaches itself to 
the stem of its host, about which it twines, robbing it of 
nourishment by means of its little suckers. 

Preventives. The seeds of dodder are somewhat smaller 
than those of clover or flax, and hence may be separated 
from the latter by careful sifting. Badly infested ground 
should be devoted for two to four years to a crop not at- 
tacked by the dodder. 

b — Plants as affected by fungous parasites. 

321. The Fungi constitute an extensive class of plants 
that derive their nourishment wholly from organic 
matter. Many of them are injurious to cultivated 
plants. Unlike the harmful insects, most of which work 
their ravages within full view, the fungi are, in very many 
cases, discernible only with the microscope, and reveal their 
presence only by the death or injury of their host. The 
fungous parasites are very numerous and exhibit great di- 
versity of structure and habit. Some of them live only upon 
enfeebled plants, while others attack perfectly healthy ones. 
Some, as the pea mildew, grow upon the surface of their 
host, drawing their nourishment through the epidermis; 
others, like the peach curl and oat smut, grow within the 
tissues of the plant upon which they feed. All of the latter 
class send their fruiting parts to the surface of the host 
plants to disseminate their m} r riads of spores in the open air. 

* Cuscuta trifolia, C. Epilinum. 



1 66 Principles of Plant Culture. 

The fungi multiply from extremely minute spores (53) 
that are produced in immense numbers, and when mature, 
are very readily blown about by the wind. Man}' of them 
also multiply from thread-like organs called mycelia (my- 
ce'-lia), something in the same manner as Canada thistles 
multiply from their roots. 

Wl'2. Methods of Controlling Fungi are of three 
classes: 

a — Removing and destroying the affected parts; 

b — Preventing the germination of the spores; 

c — Destroying the fungus itself by applying some de- 
structive material, (a fungicide (fun'-gi-cide)). 

3*23. Destruction of the Affected Parts is the most 
effectual preventive known in cases where the fungous dis- 
ease attacks a portion of the plant whence it spreads to the 
remaining parts, as in the black knot of the plum,* the 
blight of the pear, apple and quince,! and the red rust of 
the raspberry and blackberry. % 

The affected part should be removed as soon as discovered, 
and burned at once, to destroy any spores of the fungus it 
ma}' contain or which might mature later. It is generally 
important to cut the diseased branch some distance below 
the point of visible infection, as in many cases the mycelia 
of the fungus extend farther than external appearances 
indicate. 

Wl\, Preventing Spore Germination is the only 
known method by which we can combat the fungi develop- 
ing within the host plant {endophytic (en-do-phy'-tic) fungi). 

In fungi that develop from spores planted with the seed, 
as the smuts of the small grains, spore germination may be 



* Ploicrightia morbosa. f Microccocus amylovorus. % Cceoma luminatum. 



Plants as Affected by Fungous Parasites. 167 

prevented by treating the seed with a solution of certain 
chemicals or with hot water. Of the former, sulfate of cop- 
per (copper sulfate, blue vitriol, bluestone) has been most 
used, and unquestionably destroys the spores of the smuts, 
but it has generally been found to more or less injure the 
germination of the seed. 

325. The Hot=Water Treatment has proved fully as 
successful as the preceding method in disinfecting the seed, 
without affecting its vitality. This treatment consists in 
immersing the seed for ten minutes in water at a temper- 
ature of 132° F. For treating a quantit}* of seed, some 
special provisions are necessary, as it is somewhat difficult 
to bring every seed in contact with the water at the proper 
temperature. Provide two large vessels, as two kettles over 
a fire, or two boilers over a cook stove, — one to contain 
warm water (110-120° F.), the other to contain scalding water 
(132-133° F.). Place a reliable thermometer in the hot-water 
vessel that the temperature may be watched. The warm 
water is used to warm the seed, preparator} T to dipping it in 
the hot water. Without this precaution, it will be difficult 
to maintain the temperature of the latter. The seed is 
placed in a covered basket, preferably of wire cloth, in 
quantity not exceeding one-eighth of the volume of the 
water, and the basket should be but partially filled. Im- 
merse the basket several times in the warm water a moment 
at a time, giving it a rotary motion in order to bring every 
seed in contact with the water. Then plunge it into the hot 
water and repeat the immersions as before, carefully watch- 
ing the thermometer in the meantime. Should the temper- 
ature fall below 132°, cautiously add water of a still higher 
temperature; and if it rises above this point, add cold water. 



1 68 Principles of Plant Culture. 

After the seed has been in the hot water ten minutes, 
remove the basket and plunge it into cold water, then spread 
it out to dry. The drying need not be thorough unless the 
seed is to be stored for a time. 

326. Fungi that Develop from Spores Surviving the 
Winter In or Upon the Soil, as the onion* and cornsmuts,f 
cannot be prevented by disinfecting the seed. For these, we 
must depend upon surrounding the seed with some fungicide 
that wiH prevent infection of the young plant without affect- 
ing germination. For onion smut, a mixture of flowers of 
sulfur and air-slacked lime, sown with the seed, has proved 
decidedly beneficial, and is inexpensive. No preventive has 
yet been found for the corn smut. 

327. Fungi the Spores of which Survive the Winter 
Within their Dead Host Plants, as in the club-root of the 
cabbagej and turnip, and the onion mildew,^ may be held 
in check, to a degree, by burning the fungus-killed plants 
at the close of the season. 

328. Fungi that Infect their Host from Spores De= 
posited On the Aerial Parts of the plant, as the scab of 
the apple || and pear, and the down}^ grape-vine mildew \ may 
be held in check by applying a fungicide (321) to the host 
plant itself, to destroy the spores as they alight upon it. 
Various compounds of copper and of sulfur are destructive 
to the spores of fungi, and, when properly applied, are 
harmless to the plant. The copper compounds are more 
generall}' satisfactory, since they have the greater adhesive 
power. 

* Eurocystis Cepuhr. f Ustilago Maydis. 

% Plasmidlophora Brassicce. \ Peronospora Schleideniana. 

| Fusicladium dendriticum. fl Peronospora viticola. 



Plants as Affected by Fungous Parasites. 169 

329. The Bordeaux Mixture, which consists of a com- 
pound of copper sulfate (323) and lime, is now extensively 
used to prevent many fungi of this class. A standard for- 
mula for the Bordeaux mixture is: Dissolve 6 pounds of cop- 
per sulfate in J+ gallons of hot water; in another vessel slack J+ 
pounds of fresh quicklime in Jf. gallons of {hot or cold) water. 
When both are cool, pour the contents of the two vessels together 
and add enough water to make JfO gallons of the whole. Metal 
vessels, other than those of brass or copper, should not be used. 





^m ■ HP 



Fig. 75. A scab spot magnified. 
(After Trelease). 




Fig. 74. Apple affected with scab. Fig. 76. Section through a scab 

(the dark spots). Fusicladium dendriticum. spot, highly magnified. The egg- 

(After Scribner). shaped parts on the right are the 

spores. (After Trelease). 

The hot water is recommended only to hasten the dissolv- 
ing of the copper sulfate. Cold water may be used by sus- 
pending the sulfate therein, in a sack of coarse texture, a 
day or two in advance. 

Prepared by the above formula, the Bordeaux mixture often 
contains more lime than is needed for the chemical action 
that occurs. To avoid this excess of lime, a chemical test 

may be used, as follows: Pour only half of the slacked lime 
11 



170 Principles of Plant Culture. 

and water into the copper sulfate solution; stir well, and 
add a few drops o\' a 20 per cent, solution of potassium fer- 
rocvanid. If a rich, reddish-brown color is produced, add 
more lime. Continue to test and add lime until the reddish- 
brown color no longer appears. Then add a little more 
lime, as a slight e.ccess of lime is desirable. A bright, clean 
knife blade may also be used as a test. If a slight film of 
copper forms upon it when placed in the mixture, more lime 
is needed. The Bordeaux mixture is preferably strained 
before use, and should be kept well stirred during its appli- 
cation. It may be applied with any good spra} T pump. 

The arsenical compounds (284) may be added to the Bor- 
deaux mixture, and thus a single treatment will serve both 
for insects and fungi. 

%'M). The Diseases Preventable by Bordeaux Mix= 
ture are the apple and pear scab (32S), the downy mildew 
and black rot* of the grape, the early t and late blight + of 
the potato, the goosebeny mildew, 2 the leaf-blight of the 
pear, || and some others. 

In all these diseases, however, the treatment is preventive 
rattier than curative. The first application should be made 
before the disease appears, and should be followed occasion- 
ally by others as new foliage is formed, or as the material 
is washed off by rains. 

331, Ammoniacal Solution of Copper Carbonate 
possesses nearly the same fungicidal properties as Bordeaux 
mixture, but adheres less strongly to foliage. Being a solu- 
tion, it requires no straining or stirring, and it leaves a less 
decided stain on drying than the Bordeaux mixture, which 

* Lcestadia Bidwellii. t Wtcrotportum Solani. X Phytophthora infestans. 

$ Sphoerotheca Bfors-uwe. Bnlomosporium maculalum. 



Plants as Affected by Fungous Parasites. 171 

makes it preferable to the latter for use upon plants of 
whieli the fruit is nearly mature. To make this solution, 
dissolve one and a half ounces of precipitated copper carbon- 
ate in one quart of strong commercial ammonia, and add 
this solution to 25 gallons of water. The ammonia should 
be procured in a glass or earthen vessel, and should be 
kept tightly corked. To prevent waste of the ammonia by 
evaporation, add the solution to the water immediately be- 
fore spraying. 

WWZ. Potassium Sulfid Solution is used to some ex- 
tent to prevent gooseberry mildew (330)j and a few other 
diseases, but it is less enduring in its effects than the cop- 
per compounds. To prepare it, dissolve one-half ounce of 
potassium sulfid (sulfuret of potassium, liver of" sulfur) in 
one gallon of water and apply immediately. The sulfid is 
best dissolved in a little warm water and then diluted. 

\\\\\\ % Moisture Favors Spore Germination, hence a 
free circulation of air through the orchard and vineyard 
tends to prevent fungous diseases. Branches of fruit trees 
should not be permitted to hang near the ground, and 
weeds should be kept down. 

Bunches of grapes are sometimes inclosed on the vine, in 
paper bags, to keep them dry, and thus preserve them from 
fungous attack. Grape vines sheltered from rains by a 
cornice are seldom much troubled with fungous diseases. 

334. Fungi that Develop chiefly on the Outside of the 

Plant (epiphytic (ep-i-phyt'-ic) fungi), are as a rule readily 
controlled by sulfur, either in the form of " flowers of sulfur," 
or the solution of potassium sulfid (332). To this class be- 
long the powdery mildews of the grape,* apple f etc. 

* Uncinula spiralis. f Podosphwra ozycanthie. 



iji Principles of Plant Culture. 

:{;J5. The Cultivator will often Need to Consult the 
specialist in dealing with fungous diseases. In many 
cases, it will be difficult or impossible for him to deride as 
to the exact nature of a given trouble without careful train- 
ing, and skill in the use of the compound microscope. Spe- 
cialists in this line are now employed by the governments 
of most civilized nations, and by many agricultural experi- 
ments stations, and they should be freely consulted. Much 
may be learned, however, by studying the best books on the 
subject. The cultivator should learn to recognize the prin- 
cipal fungous diseases. 

Section VII. The Plant as Affected By Weeds 

836. Weeds are plants that, while not parasitic, persist 
in growing where they are not wanted. They injure the 
desirable plants about which they grow, by robbing them of 
light, moisture and food, and their presence is an evidence 
o( slovenly culture. The remarkable vigor and prolificacy 
possessed by man}- weeds enable them to overcome most 
cultivated plants, which they would soon subdue but for the 
aid of the cultivator. As with harmful insects and fungi, 
prompt and persistent efforts are most essential to the con- 
trol of weeds in cultivated grounds. 

:{:{?. Annual, Biennial and Perennial Weeds. With 

reference to their term of life, weeds and other plants, are 
divisible into three classes, viz.: annual, those that live but 
one season; biennial, those that live onty two seasons; and 
■perennial, those that live an indefinite number of seasons. 
Those of the first class usually seed most abundantly, and 
hence they are most widely distributed and appear in culti- 
vated grounds in the greatest numbers. Those of the third 



Plants as Affected by Weeds. 173 

class are commonly most, tenacious of life and are therefore 
often most difficult to control. 

!{I{S. Annual and biennial weeds, since they have a defi- 
nite life period, and multiply almost exclusively by seed, 
may be effectually controlled by preventing seedage. To 
accomplish this with certainty, the plant should be destroyed 
before bloom, as many species possess enough reserve food 
to mature seeds sufficiently for germination, if cut while in 
flower. 

;{!{*). Perennial weeds often multiply by suckers as well 
as by seeds. Since the underground stems or roots, whence 
the suckers grow, are hidden beneath the soil and are often 
extremely tenacious of life, weeds of this class are fre- 
quently very hard to eradicate. 

Persistent prevention of leafage, by starving the proto- 
plasm of the roots, is always a sovereign remedy, though it 




I'm. 7'j. Showing how plants of the -ow thistle multiply from underground stems, 
is often extremely difficult to apply in practice, since the 
suckers of some species grow with great rapidity. Yet, as a 
whole, no better remedy is known. Frequent plowing and 
cultivation of the infested ground is usually the most effect- 
ual means of preventing leafage. 

Certain very tenacious perennial weeds, as the Canada 
thistle,* and the sow thistle,! when growing on deep, rich 

* Cnicus arvensis. | Sonehua arvemis. 



i;} Principles of Plant Culture, 

loams in which the horizontal roots extend freely below the 

plow line, may, it is said, be crowded out by seeding the 
land to grass, at a loss oost than they oan be subdued by 
the plow. 

Saving now carefully studied the round ol plant life, and 
how plants are afieoted by unfavorable conditions oi' envi- 
ronment, we are prepared to enter upon a more advanced 

Stage ol' oulture, ami to learn how to cause new plants to 
grow, and how to so treat the plants thus grown that they 
mav best serve our purpose. 



The following books are recommended for reading in con- 
nection with the preceding chapter: Elementary Meteorol- 
ogy, Davis; Chemistry o( the Farm, Warington; Agricul- 
ture, Storer; The Spraying of Plants, Lodeman; Keonomie 
Entomology, Smith; Manual for the Study o\' Insects, Corn- 
stock; Fungous IMseases o( the Grape and Other Plants, 
Lamson-Scribner. 



CHAPTER IV. PLANT MANIPULATION 
Section I. Plant Propagation 

340. Propagation, as the term is generally need in 
plant culture, is the artificial multiplication of plantt i e 
reproduction (16) encouraged or induced by the knowled 
skill and care of the cultivator. 

Theoretically, any part of a plant containing living proto- 
plasm, wit.li sufficient assimilated food or tissue capable of 
assimilating food, may, under proper conditions, develop 
into a complete plant. But in practice, wc have not yet 
been aide to fully accomplish this end; for example, the 
roots and leaves Of some plants have not he-en induced to 
form buds. 

341. Plants are Propagated by Numerous Methods, 
but only two of these are distinct in kind. viz.. by feed 
and by division of the plant In propagation by seeds, the 
embryo of the seed (54) is the vii.al center vrhence the hew 
plant is developed. In propagation by division, a living hud 

(128) from the parent plant, or a hit of tissue capable Of 

forming a hud. is substituted for the embryo of the seed. In 
seed propagation, tin; resulting plant is the product of sex- 
ual fecundation (150), and hence cannot be considered as 

strictly a part of the parent. Tt does not necessarily re- 
semble tin; parent closely. In propagation by division, on 
the other hand, the resulting plant may be regarded as 
simply a continuation of the growth of the parent in a new 
location, and with rare exceptions, very closely resembles 
the parent. 



176 Principles of Plant Culture. 

34'i. Propagation by Seeds is commonly practiced 
with annual and biennial plants; also with perennials in 
which the reproduction of the exact parental form is unim- 
portant, as in the cereals, forest trees, and seedlings intended 
for grafting. This method is also used when it is desired 
to secure variation in the progeny, as in developing new 
varieties (4385). 

343. Propagation by Division of the plant is used 
when it is desired to reproduce the exact parental form, as 
in fruit- and the finer ornamental trees, many flowering 
plants etc.; also, in certain plants that are more readily 
multiplied by division than by seeds, as mint, and many 
other perennial herbs; and in other plants that rarely or 
never produce seed, as the horse-radish, sugar cane, banana 
etc. 

A — Propagation by Seeds 

344. This is the most common method of propagating 
plants. It seemed appropriate to give most of the needed 
directions for planting seeds in the first two sections of 
Chapter IT. We add, therefore, only a few general rules 
deduced from the principles there stated. 

a. The soil in which seeds are to be planted should be thor- 
oughly crumbled, because the seeds must have access to the 
oxygen of the air, or they cannot germinate (31). 

b. 7 y he well-crumbled soil should be compactly pressed about 
the seeds, because the seeds cannot absorb moisture rapidly 
unless the seed-case is in contact with the moist soil par- 
ticles at many points (27b). 

c. The soil shoidd be moist, but not wet enough to puddle 
(31). [f it is wet enough to puddle, the oxygen is likely to 
be shut out from access to the seeds (35). 



Propagation by Division. 177 

d. Seeds should be planted no deeper than is necessary to 
insure the proper degree of moisture ; otherwise, the plantlet 
expends needless energy in reaching the surface (48). Very 
small seeds should be only slightly covered, if at all, and 
must receive artificial watering, if necessary (52). Spores 
must not be covered with soil at all (53). 

B — Propagation by Division 

345. We have seen (340) that a part of a plant, placed 
under favorable conditions, is usually capable of developing 
into a complete plant. A section or cutting of the stem, for 
example, that has no roots at the time it is cut off, may 
often be caused to form roots, and thus become a complete 
plant. A cutting of a root may, in many cases put forth a 
bud, which in turn may develop into a shoot, and form 
leaves, flowers and fruit. Again, we have seen (70) that 
portions of cambium from different, nearly-related plants 
may unite by growth, which enables us to change undesir- 
able seedlings into valuable sorts by grafting (383). These, 
and certain other methods of multiptying plants, come under 
propagation by division. 

In propagation by division, the presence 0/ at least one healthy 
groiving point on the part selected for the propagation is gener- 
ally essential to success and is always helpful. 

34(>. Two Methods of Propagation by Division may 

be distinguished, viz., by parts intact, and by detached parts. 
In the first, the part selected for propagation is not sepa- 
rated from the parent until the organs needed to make it 
self-supporting are formed; or if a cion (383), until it has 
united to the part on which it is intended to grow. In the 
second method, the part intended for propagation is severed 
from the parent at the outset, and placed under conditions 



178 Principles of Plant Culture. 

favoring the formation of the organs needed to make it self- 
supporting; or if a cion, favoring its union with the stock 

(383). 

a. Propagation by Parts Intact. 

This method is applicable to many plants, and has the 
advantages of being reliable and requiring little skill. The 
part selected for propagation, being nourished by the parent 
until it forms the needful organs, is able to endure unfavor- 
able conditions that would prove fatal in most other meth- 
ods of propagation. This method includes four divisions, 
viz., propagation by suckers (347), by stolons (348), bj^ layers 
(349), and by approach grafting (399). In the first two, the 
propagation is performed by the parent plant without other 
aid than the maintenance of a well-aerated, moist and clean 
soil that stimulates the production of the needed organs, 
which in these cases are roots. 

347. Propagation by Suckers. Suckers are shoots 
that originate from roots or underground stems and grow 
upward, forming young plants about the parent, as in the 
blackberry, plum, choke-cherry etc. The propagation con- 
sists in simply cutting off the stem or root whence the 
sucker proceeds, and transplanting the latter. 

The growth of suckers may generally be stimulated, in 
plants that naturally produce them, by cutting off the roots 
or underground stems from which they grow, or by severely 
pruning the top. 

The propagation of woody plants from suckers is not 
considered wise as a rule, since the roots are usually poorly 
developed in proportion to the stem, and some plants grown 
in this manner seem to acquire the tendency to form suck- 
ers excessively. In the red raspberry* and the blackberry,! 

* Rub us slriyosus, R. Idceus. f R. villosits. 



Propagation by Parts Intact. 



179 




however, propagation by suckers is by far the most conven- 
ient method, and it appears to be followed by no bad 
results. 

348. Propagation by Stolons. A stolon is a branch 
that starts above or at the surface of the ground, and either 

grows prostrate, or curves 
downward till it reaches the 
ground, where it takes root, 
usually at the nodes (116). The 
currant, juneberry, cranberry, 
and man} T herbaceous plants are 
readily multiplied in this way. 
Stolons often root without as- 
, sistance, but the rooting is 

Fig. 80. Sucker plants 01 the red ' ° 

raspberry, Rubus sirigosus. a, before much hastened and encouraged 

growth has started; B. alter. The two i • .-, ■, , ... 

u . / o + *• ■ + k *u by covering the branch with 

shoots of B starting just above the J & ^^^ " 1UU 

roots form the new canes. soil. When Well rooted, the 

young plants may be separated from the parent by cutting 
the stolons. 

Woody plants grown from stolons are seldom uniform in 
size, and are not often as 
well rooted as those grown 
from cuttings (358). Some 
herbaceous plants are, how- 
ever, more readily propa- 
gated by stolons than by an} T 
other means. 

The offset, by which the 
houseleek * is so r e a d i 1 y FlG 81 Tip plant of black raspberry . 

propagated, is a very Short The bud, whence the young shoot starts, 
, . . appears at the base of the parent cane. 

stolon that forms a single (After Bailey). 

* Sempervivum. 




i8o 



Principles of Plant Culture. 




tuft of leaves at its apex. The cane of the black -cap rasp- 
berry,* which roots from the tip (Fig. 81), and the runner of 
the strawberry (Fig. 82), that forms a plant at each node, 
are modified stolons. 

349. Propagation by Layers or Layering. The layer 
is an artificial stolon, i. e., a branch that does not naturally 

grow downward, which 
is covered with, or sur- 
rounded by moist soil 
to stimulate the pro- 
duction of roots (89). 
The branch may be 
bent down and cov- 

Fio. 82. Runner of the strawberry, Fragaria. ered, as is USlially prac- 
ticed with the grape, wisteria etc., or the soil may be ridged 
up about the branch, as is done with the quince and para- 
dise apple. In either case, the terminal portion of the stem 
should be left uncovered. In the latter method, which is 
known as mound-layering (Fig. 83), the stems are usually 
cut off just above the surface of 
the ground in early spring, to 
stimulate the formation of vig- 
orous shoots, which are ridged 
up about midsummer, or, pre- 
ferably, not until the succeed- 
ing fall or spring. The ridging "^ 

Should be Sufficiently high tO Fl(J g3 M ound-layering of goose- 
COVer Several Of the lower nodes berry plants. (After Bailey). 

(116). Roots grow out at the nodes, and the shoots are 
usually well rooted by the autumn following the ridging. 







'Ji 



* JRubus occidentalis. 



Propagation by Parts Intact. 



181 




Man}' woody plants that do not readily form roots when 
layered, ma}' be induced to do so by mutilating the stem 
somewhat in the 
covered part. This 
tends to restrict 
the growth current 
(80) and causes an 
accumulat ion of 
reserve food, from 
which roots may 
originate. Gird- 
ling, twisting, 
bending or splitting 

the Stem for a Short FlQ g4 Layered branch of currant, split to encour- 
distance will Often age the formation of roots. 

have the desired effect (Fig. 84). 

Layering is a very reliable and expeditious method of 
propagating many woody and herbaceous plants. 

350. Propagation by Division of the Crown of the 

plant, which is practicable with many perennial herbs, as 
the rhubarb, dahlia, globe artichoke etc., though not strictly 
analogous to propagation by stolons or layers, may be con- 
sidered here. It consists in taking up the plant, preferably 
while dormant, and cutting the crown into two or more 
parts, according to its size or the number of plants desired, 
and planting the divisions as separate plants. This method 
is applicable to propagation for private use, rather than for 
sale purposes. 

Propagation by approach grafting, although in order here, 
is more readily treated with the other methods of grafting 
(399). 



182 



Principles of Plant Culture. 



B. Propagation by Detached Parts. 

This comprises two quite different modes of propagation, 
viz.. by specialized bud*, and by sections of the plant. 
a— Propagation by Specialized Buds. 

351. This includes propagation by bulbs, bulblets, eorms 
and tubers. It is in a sense intermediate between propa- 
gation by parts intact (346), and by cuttings (35S). The 
bud that is to form the future plant, though not haying 
roots of its own, has been specially prepared by the parent. 
through an abundant food supply and a partially dormant 
condition of the protoplasm, to maintain a separate exist- 
ence, even under adverse conditions, and in due time, to 
develop into a plant. In these respects it resembles the 
seed, from which it differs, however, in 
the less dormant condition of its pro- 
toplasm, and in not being the product 
of sexual fecundation (341). 





Fig. 85. Fig. 86. Fig. 87. , Fig. 88. 

Fig. 85. Bulb of the coruniou oniou, Allium cepa. B, buds. 
Fig. S6. Bulb of garlic, Allium sativum. It contains several smaller bulbs 
(clove- 
Fig. 87. Bulb of wild lily. 
Fig. SS. The same divided lengthwise, showing buds, B. 

352. The Bulb is a very short stem containing a ter- 
minal bud which is inclosed in scales (128). The scales are 



Propagation by Detached Parts. 



183 



thickened by a store of food, and in their axils are smaller 
lateral buds. The terminal bud usually develops into a 
flower, and thus perishes. One or more of the lateral buds 
may develop into flower-buds for the next } r ear, and thus 
continue the life of the plant, as in the common onion (Fig. 
85); or the lateral buds may develop at the expense of the 
parent, as in the potato onion. 

\\W>\. Bulblets, or Bulbels, are small bulbs formed in 
the axils of the leaves in certain plants, as the tiger lily,* 
(Fig. 89)j or at the apex of the stem, as in the " top " or bulb- 
bearing onion (Fig. 1)0). 





Fig. 89. Fio.90. 

I i'. 89. Bulblets in axils of leaves of tiger lily. 

Fig. 90 Bulblets of " top" onion, sometimes used as onion "sets." 

354. The Corm (Fig. 91) differs from 
the bulb chiefly in being without scales. 
The food is deposited in the thickened 
stem. The corms of our flowering plants, 
as the crocus, cyclamen etc., are generally 
called bulbs in commerce. 

855. The Tuber, of which the com- Fi«. 91. cormofcro- 

cus, with small corms 

mon potato is the most familar example, (bud8) for following 

differs from the corm in being the end of y ear - 

an underground branch of the stem (115), instead of de- 




* Lilium tiyrinum. 



184 Principles of Plant Culture. 

veloping in direct contact with the parent. It also has 
more numerous buds (eyes) than the corm. 

356. Propagation from Bulbs, Bulblets, Corms, and 

Tubers is a very simple operation, and consists merely in 
planting these parts in the place where the plants are de- 
sired. Tubers may be cut into pieces containing one or 
more buds each, if desired. The rules given for planting 
seeds (344) apply equally well here. All should be stored 
for preservation in a cool, moderately-dry place, that is free 
from frost. They retain their vitality but a single year. 

In the methods of propagation thus far considered, with 
the sole exception of la3 r ering (349), advantage has been 
taken of a natural mode of plant multiplication. The skill 
of the cultivator, however much it may assist the processes, 
is not necessary to their success, since wild plants habitually 
increase by the same methods. We will now consider a 
method which is far less often illustrated in nature, and in 
which the skill and care of the cultivator are, as a rule, 
essential to its accomplishment, viz. : 

b — Propagation by Sections of the Plant. 

The various methods of propagation in this division are 
alike in the fact that a detached part of the parent plant, 
containing living protoplasm, is placed for a time under 
specially favorable conditions, in virtue of which the part is 
enabled, not only to live, but to perform its functions and 
reproduce the needed organs, or if a cion (383), to unite by 
growth to the part with which it is placed in contact. 

357. In propagation by sections of the plant we must, 
of necessity, wound the plant tissues in securing the parts 
for propagation. Since it is alwa} T s desirable that the 
wound should heal promptly (73), it is very important that 
the cutting tools used should have sharp and smooth edges. 



Propagation by C tit ting's. 185 

As here considered, propagation by sections of the plant 
includes two methods, differing materiall}' in their require- 
ments and in the manner of development of the plants, viz., 
propagation by cuttings and by grafting. 

a — Propagation by Cuttings. 

358. A Cutting is a detached member of a plant in- 
tended to be placed in the soil, or some other medium, for 
propagation (340). It may be in an active, or a dormant 
state (13) and may or may not contain a growing point (67). 
Before the cutting can become a plant, it must develop the 
essential part or parts of the plant that it lacks; i. e., the 
stem and the leaves, or the root, or all these members. 
Cuttings of the stem are usually planted with their proximal 
(116) end in the soil, and their distal end in the air. Root 
cuttings are generally covered in the soil. 

359. Nearly All Plants may be Propagated by Cut= 
tings from one or another of their parts. The ease with which 
plants ma}- be multiplied in this way varies greatly in differ- 
ent species (21), and even in different varieties of the same 
species. The external appearance of a plant is not always 
an indication of the facility with which it may be grown 
from cuttings; the only sure way to ascertain this is by trial. 

Climate exerts a marked influence upon the tendency of 
plants to develop from cuttings. In certain locations in 
southern Europe, and in parts of South America, branches 
of the common apple tree, sharpened and driven into the 
ground as stakes, often take root, and sometimes even bear 
fruit during the same season. A warm, moist atmosphere 
is very favorable to propagation by cuttings. 

We have seen that the roots of certain plants normally 

develop buds (131). In like manner, the stems of many 
12 



1 86 Principles of Plant Culture. 

plants, as the potato, grape etc., normally develop growing 
points of roots at their nodes (116). Plants that normally 
develop buds upon their roots or growing points of roots at their 
nodes are readily propagated by cuttings. But propagation 
by cuttings is not limited to such plants (362). 

360. The Essential Characteristics of a Cutting 

are a — a certain amount of healthy tissue; b — a certain 
amount of assimilated food, or of tissue capable of assimi- 
lation, i. e., chlorophyll-bearing (green) tissue; c — in most 
species, a growing point (67), either of the stem or root, or 
of both. 

361. The Parts of plants to be Used for Cuttings, 
therefore, are preferably the } T ounger, matured growths, 
since the tissues of these are most vigorous; or else a part 
that possesses a certain amount of healthy and vigorous 
leaf tissue. The cutting should always contain one or more 
buds when practicable (128). 

362. Conditions that Favor the Growth of Cuttings. 
a — A soil warmer than the air above it (" bottom heat ") is 

important in growing plants from cuttings. Warmth stim- 
ulates plant growth, and when applied to one part of a plant, 
it stimulates growth in that part. If the soil about a planted! 
cutting is warmed to a temperature considerably higher 
than that of the air above, the growth of roots is stimulated. 
Indeed bottom heat often excites growth in cuttings that 
will not grow without it. 

b — A comparatively low air temperature is important in 
growing plants from cuttings of the stem (377) because it is 
essential that the stem growth be held in check until roots 
are formed. A soil temperature of about 65° F., with an air 
temperature about fifteen degrees lower, is suited to the great 



Propagation by Cuttings. 187 

majorit} T of plants usually propagated under glass from cut- 
ings. It is important that these temperatures be maintained 
nearly constant until roots have developed. 

Since we have better facilities for raising, than for lower- 
ing the natural temperature of the atmosphere, propagation 
from cuttings is easiest at a time of the year when the tem- 
perature of the atmosphere during the day does not much 
exceed 50°. By observing special precautions, however, it 
is possible to propagate many plants from cuttings during 
the warm season. 

c — Abundant moisture is important in growing plants 
from cuttings, because moisture favors root development 
(89), and water is essential to cell growth (63). The amount 
of water required varies considerably with different plants 
and conditions. 

With cuttings containing leaf tissue (377, 382), transpira- 
tion (75) must be reduced to the minimum until roots are 
formed, because water cannot be taken up freely without 
root-hairs (101). For such cuttings, therefore, the air, as 
well as the soil, must be kept abundantly moist (369), and 
the direct rays of the sun must be intercepted by shading 
(236). 

363. Methods for Controlling Temperature. The 
alternations of temperature in the open air are unfavorable 
to the development of cuttings. Some structure, therefore, 
that may confine warmth radiated from the earth, or artifi- 
cially generated, or that may when necessary shut out a 
part of the solar heat, is always of great assistance in pro- 
pagating plants from cuttings, and in many species, is essen- 
tial to success. Since light is necessary to assimilation (59), 
such a structure must be roofed with glass, or some other 
more or less transparent material. 



i88 



Principles of Plant Culture. 




3<>4. The Cold=Frame (Fig. 92) is the simplest struc- 
ture of this kind. It consists of a frame, or box without 
bottom, usually shallower on one side than on the other, 
covered with glazed window sash.* The frame is generall}' 
placed so that its shallower side faces the south, thus giv- 
ing its cover a southward slope. It has no provision for 
artificial heat, though when covered with glass, the temper- 
ature within the 
frame is much 
increased during 
sunshine, owing 
to the property 
possessed by 

Fig. 92. Cold-frame, with sash lifted for ventilation. glaSS of Confining 

the heat rays. The cold-frame should be protected in freezing 
weather by an additional cover of mats or blankets, while 
excessive sun heat should be avoided b} T shading (230). 
Muslin- or paper-covered frames require no shading. 

Although affording no bottom heat (362a), the cold-frame 
may be used for propagating many plants from cuttings. It 
is also serviceable in connection with the propagating bed 
(368), for "hardening off" young plants grown from cut- 
tings in the latter, as well as for growing very many plants 
from seed. Set over a pit in the earth, the cold-frame 
makes an excellent place (cold pit) for wintering half-hardy 
plants. 

365. The Hotbed differs from the cold-frame in having 
bottom heat (362a), which is usually supplied by the fer- 
mentation of moist vegetable material, as horse manure, 



* Muslin or paper is sometimes used instead of glass, aud these materials may 
be rendered waterproof, and less opaque, by painting with linseed oil or some 
similar material. 



Propagation by Cuttings. 



189 




Fig. 93. Cross section of hotbed in pit. The frame is 
banked up a little with earth. (After Greiner). 



leaves, refuse hops or tan-bark. The material intended for 
heating, if fresh, should be thrown into a pile of sufficient 
size to generate heat, several days before it is desired for 
use; and unless already moist, it should be moderately 
sprinkled with water. In order that all the material may 
reach the same 
stage of fermen- 
tation, the mass 
should be made 
into a new pile 
after the heating 
starts vigorous- 
ly, as is indica- 
ted by vapor ris- 
ing from the 
heap, and the 
outer part of the mass should be placed in the center of the 
new pile. Leaves ferment slower than the other materials 
above named, and hence may often be advantageously mixed 
with them to lengthen the period of fermentation. 

Heat is economized by placing the fermenting material 
in a pit in the ground, but hotbeds are often made above 
ground. The hotbed pit should be in a well-drained and 
sheltered place, and two to two and one-half feet deep. In 
this, the heating material should be moderately packed, 
until the pit is nearly or quite full. The frame may then 
be placed over the pit, after which the heating material 
should be covered with soil and the sash put on to confine 
the warmth. Within a few days after covering with the 
sash, the fermenting material usually generates a rather 
violent heat, which should be permitted to decline to about 
90° F., before planting seeds or cuttings in the hotbed. The 



190 



Pj'incifles of Plant Culture. 



same protections against excessive heat or cold are used as 
for the cold-frame; but the hotbed requires much the more 
care in ventilation, since the heating material generates 
vapor and carbonic acid, as well as heat, and these, when 
present in excess, are detrimental to plant growth. 

366. The Greenhouse is an expansion of the hotbed, 
i. e., a structure sufficiently large so that it may be entered, 
and with arrangements for heating by fire* In temperate 
climates, greenhouses are usually constructed 12 to 22 feet 
wide, with a gable or M roof, having a slope of 35° to 40°, 
covered with glass and with the ridge or ridges extending 
north and south (Fig. 94); but in very cold climates, a shed 
roof facing the south is preferable. Greenhouses are often 
built with one slope of the roof longer and less steep than 
the other, and with the ridge extending east and west. 
Such a roof is called a " two-thirds-" or " three-quarters 
span," according as the longer slope covers two-thirds or 

three-quarters 
of the width 
of the house. 
The long slope 
usually faces 
the south, but 
houses have 

Fig. 94. Cross section of greenhouse. (After Grenier). yppprifly been 

built with the shorter and steeper slope facing the south, a 
plan thought to possess advantages for growing certain 
plants, as carnations. 

Provision is made for ventilation in glass houses by plac- 
ing a certaiu number of movable sash in the roof or else- 




* Hotbeds are now being heated by fire to some extent. 



Propagation by Cuttings. 191 

where. In order that the glass ma} 7 not be far above the 
plants, the side walls should not exceed five feet in height. 
These may be of any durable material, but a wall of brick, 
ten inches thick, with a two-inch air space in the center, is 
to be preferred, since it best economizes heat. The furnace 
and potting rooms obstruct the light least, and afford the 
most protection when located so as to form the north wall 
of the house. In houses extending north and south, the 
south end is usually glazed above the height of the side 
walls. 

307. Heating Devices for the Greenhouse are of 

various kinds. The " smoke flue " is simplest, and cheapest 
in first co3t. It consists of a flue extending from the fur- 
nace, which is placed somewhat below the floor level, length- 
wise through the house, preferably rising gradually to a 
chimney at the opposite end. Or the flue may cross the 
farther end of the house and return at the other side, to a 
chimney built directly upon the furnace. The latter method 
usually gives better draft, since the warmth from the fur- 
nace stimulates an upward current of air through the 
chimney. The flue should be of brick for the first 25 feet 
from the furnace, as a safeguard from fire. After this, it 
ma}' be of cement or vitrified drain pipe. 

Greenhouses of the better class are now almost invariably 
heated with steam or hot water, or with a combination of the 
two. Pipes from a boiler, located beneath the floor level, 
extend nearly horizontally about the house, beneath the 
benches, returning to the boiler; or the main feed pipe ex- 
tends overhead to the farther end of the house, where it 
connects with a system of return pipes beneath the benches. 
While the steam- or hot-water heating costs much more at 



192 Principles of Plant Culture. 

the outset than the smoke flue system, * it is generally found 
not less economical, and far more satisfactory, in the long 
run. Where the pipes need to make many turns, steam is 
more satisfactory than hot water. 

368. The Propagating Bed. A certain part of the 
greenhouse is usually set apart for propagating plants from 
cuttings. The propagating bed is made upon the ordinary 
greenhouse bench, directly over the flue or heating pipes. 
To furnish the bottom heat (362a), the space beneath the 
bench is boxed in with boards. Horizontal doors are, however, 
provided which may be opened when it is desirable to allow 
a part of the heat to pass directly into the house. The floor 
of the bench should not be so tight as to hinder drainage. 

In large commercial establishments, entire glass houses 
are often devoted solely to propagation. Such houses are 
usually eleven or twelve feet wide, with low side walls. 
Sometimes lean-to houses are built for propagation, on the 
north side of a wall, where direct sunlight is cut off. 

In making the propagating bed, a thin layer of sphagnum 
moss is usually spread over the floor of the bench, and 
covered to a depth of two to four inches with well-packed, 
clean, rather coarse sand, brickdust or powdered charcoal. 
Sometimes the whole bed is made of moss. These materials 
are used because they will not retain an excess of water if 
the proper provision is made for drainage. Sand is most 
used because it is as a rule readily obtained, but it needs to 
be selected with care, as it often contains injurious mineral 
matters. Sand found along the borders of fresh-water 

*In round numbers, the cost of the smoke flue may be estimated at ten per 
cent, of the whole outlay required in a house heated by this method, while in one 
heated with hot water or steam, the cost of the heating apparatus is not far from 
fifty per cent, of the whole. 



Propagation by Cuttings. 



J 93 



streams or lakes may generally be safely used without wash- 
ing, but that dug from sandpits should in most cases be ex- 
posed to the air for a few weeks, and then be thoroughly 
washed before being employed for cuttings. The same sand 
should be used for but one lot of cuttings as a rule, for it is 
liable to become infested with fungi that may work havoc 
in the cuttings placed in the propagating bed (368). 

369, Methods of Controlling Humidity. Where 
moisture needs to be controlled with especial care, as in 
propagating delicate plants from green cuttings, or in her- 
baceous grafting (393), the planted cuttings or the grafted 
plants are often covered with bell-jars. To guard against 
sudden fluctuations in temperature, a larger bell-jar is some- 
times placed over a smaller one. 

By means of a bell- 
jar, with a tight-fitting 
ground plate, evapora- 
tion may be wholly 
prevented from cut- 
tings or plants, if desir- 
ed. Propagating beds 
are often covered with 
glazed sash, in addition 
to the glass roof of the 
house, to assist in main- 
taining a moist atmos- 
phere about the cut- 
tings (Fig. 95.) 
For convenience, we separate propagation by cuttings 
into two divisions, viz., propagation by cuttings from dor- 
mant plants, and from active plants. The requirements of 
these two classes differ in some respects. 




Fig. 95. Propagating bed covered with glazed 
sash. 



194 Principles of Plant Culture. 

a — Propagation by cuttings from dormant plants. 

370. The Time to Make the Cuttings. We have seen 
(177) that plant processes ma}' not be wholly suspended 
during the dormant period. This is true not onl} r of the 
plant as a whole, but also of detached parts of the plant, 
if they are protected from evaporation. If cuttings are 
taken from a plant in autumn, and stored during winter in 
a moist place of moderate temperature, the cut surfaces will 
partially callus over (73), and the formation of roots or buds 
maj T commence before spring. 

When new growing points must be developed before the 
cutting can form a plant, as with cuttings of the stem and 
roots of many species, cuttings of dormant plants are prefer- 
ably made at the beginning of the dormant period, i. e., in 
autumn, and placed during winter under conditions favoring 
the formation of new growing points. 

371. The Storage of Cuttings. Cuttings should be 
stored in a place sufficiently moist to prevent loss of water 
by evaporation, and warm enough to favor moderate root 
growth. Cuttings with ready-formed buds must be kept 
cool enough to prevent growth of these. Root growth may 
proceed to some extent at temperatures too low to excite the 
buds. These conditions are usuall} T fulfilled by covering the 
cuttings in damp sawdust, sand or loose loam, and storing 
them through the winter in a moist, moderate^ cool cellar, 
or by burying them in the open ground beneath the frost 
line. In mild climates, the latter plan is often preferable to 
storing cuttings in a cellar, and stem cuttings (373) of plants 
that do not root freely from the stem are frequently buried 
with the proximal end (116) uppermost. This gives them, to 
some extent, the advantage of bottom heat, (362a) since the 



Propagation by Cuttings. 195 

surface layers of the soil are first warmed by the sun in 
spring. 

Cuttings stored in the ground over winter should be taken 
up and planted in spring before the buds expand. 

Cuttings of evergreen coniferous plants cannot be buried, 
as this would destroy the leaves, without which the\ r rarely 
form roots. Cuttings of these plants are usually made in 
autumn and planted at once in boxes of sand, which are 
kept for a time in a light, cool place, as a cool greenhouse, 
until the growing points of the roots have formed, after 
which the} r are removed to a warmer location. 

372. Planting Cuttings in Autumn. Stem cuttings 
of the currant, and other hardy plants, and root cuttings 
(376) of the blackbeny, are sometimes made as soon as the 
wood is mature in autumn, and planted at once, in well- 
drained loamy or sandy soil. Cuttings thus treated often 
commence to form roots before winter. They should be 
covered with a little earth, and mulched with some coarse 
litter on the approach of freezing weather, and should be 
shaded for a time after the opening of spring, (Fig. 63, p. 
135). 

373. Cuttings from Dormant Stems (stem cuttings) 
usually form roots more promptly if the proximal end is 
cut off shortly below a node (116). See Figs. 96, 97 and 98. 
In certain plants, as many of the conifers, cuttings root more 
promptly when cut with a heel, i. e., with a small portion of 
the wood of the previous }'ear at the base. The very short 
internodes at the junction of the two seasons' growth appear 
to favor the emission of roots. Some varieties of the grape 
root more readily when a short section of the parent branch 
is removed with the cutting, forming a mallet-shaped, or T 
shaped cutting (mallet cuttings). 



196 



Principles of Plant ( 'ufture. 



The cut forming the distal end of tke cutting is preferably 
made considerably above a node, in order that the bud 
may not lose an undue amount of moisture by evap- 
oration from the adjacent cut surface. 

Cuttings of certain plants that do not readily 

form roots when made in the ordinary way, may be 

induced to do so by "ringing" (428(2) the branch 

from which the cutting is to be made, just below a 

node, at about midsummer. Callus will then form 

at the upper edge of the ring (SO), and 

food will be stored in the stem immediately 

above it. In autumn the branch may be 

severed just below the ring, and a cutting 

made, of which the base shall include the 

callused part, and which may be treated in 

the usual manner. 

;{?4. The Proper Length 
lor Stem Cuttings depends 
upon the conditions under 
which they are to be grown. 
(Sittings containing but a 
single bnd often root freely 
and form vigorous plants, in 
the propagating bed, where 
heat and moisture may be 
readily controlled. S u c b 
short cuttings, however, are 
seldom used except when 
(After Bailey). cutting-wood is scarce. Cut- 

Fig.97. Stem cuttlngofthegrape. (After tin intended for p l ant ing 
Bailey). n r 

Fig. 98. currant, cutting rooted. in the open ground are pre- 

ferably made at least six inches long. 




Fig. 96. 
Fig. 96. 



Fig. 97. Fig. 98. 

Stem cutting of the currant 



Propagation by Cuttings. 197 

:{?.">. How to Plant Stem Cuttings. The general 

rules given for the planting of seeds (343) apply with nearly 
equal force to cuttings of the stem. Single-bud cuttings 
should be planted with the bud facing upward, and one 
half to three-fourths of an inch deep, in order that the de- 
veloping bud may readily reach the surface. Cuttings of 
more than one bud should be placed more; or less upright at 
such a depth that the bud at the distal end is about on a 
level with the surface. In cuttings of shrubby plants de- 
sired to produce a single stem, the central buds should be 
rubbed off before planting, leaving but one or two buds at 
the distal end (Fig. 96). 

376. Propagation from Cuttings of the Root. Plants 
that naturally sucker from the roots (347), and some others. 
ma} r be propagated from short pieces of the root (root cut- 
tings). For this purpose roots of the thickness of a lead 
pencil, more or less, are commonly cut into pieces one inch 
to three inches long (Fig. 99), as soon as growth ceases in 

autumn, and packed in boxes 
with alternate layers of moist 
sand or moss. The boxes are 
.. fl „ „ . M ... .. preferably stored in a cool eel - 

FlO. 99. Koot cutting of blackberry, * J 

(After Bailey). lar where they may be examined 

from time to time during winter; the sand or moss should 
be moistened when it appears dry. Root cuttings of differ- 
ent varieties of the same plant often require different degrees 
of temperature to induce the formation of callus and buds, 
hence the boxes should be frequently examined, particularly 
toward spring, in order that those in which the cuttings are 
backward in starting may be placed in a higher temperature. 
Thus treated, root-cuttings of many hardy plants, as the 




198 Principles of Plant Culture. 

plum, raspberry, blackberry, jimeberry, etc., often form both 
buds and rootlets by spring, so that they ma}' be planted 
directly in the open ground. Those of more tender species, 
as the bouvardia, geranium, etc., will not start to the same 
degree, unless placed in the propagating bed toward spring 
and given bottom heat. 

Root cuttings should be planted shallow, usually not more 
than one-half to three-fourths inch deep, in order that the 
developing bud may soon reach the light; otherwise, as in 
too-deeply-planted seeds, the reserve food may be exhausted, 
causing death of the bud. When planted in the open ground 
(372), the soil should be made very fine, and carefully 
pressed about the cuttings; if the weather is warm and dry, 
shading (Fig. 63, p. 135) and watering will be necessary. 

b — Propagation by Cuttings from Active plants (green cut- 
ings, slips). 

377. Nearly All Plants may be Propagated from 
Green Cuttings. A succulent cutting of nasturtium 
(tropaeolum), with its leaves intact, placed with its proximal 
end immersed in fresh, well or spring water, will, for a con- 
siderable time, absorb sufficient of the liquid to make good 
the loss from transpiration (75). So long as the water 
remains fresh, and the tissues of the stem are unobstructed, 
the water thus absorbed will answer the same purpose to 
this cutting as if it had been absorbed by the roots. 
Assimilation (49) will continue, and the growth current (80) 
will transport the assimilated food from the leaves into the 
stem and in the direction of the roots. No roots being 
present, however, the growing points of roots will form at 
the base of the stem, and we shall soon have a rooted cut- 
ting. Not all plants, however, can root freely in water, 
possibly owing to an insufficient supply of oxygen therein. 



Propagation by Cuttings. 199 

With very few exceptions, of which the greenhouse smi- 
lax * is one, cuttings of the succulent growth of the stem, 
with a certain amount of healthy leaf surface intact, will 
develop roots in all plants, under proper conditions of humi- 
dity and temperature; hence propagation from green cuttings 
is a very common and expeditious method of multiplying 
plants. The health} 7 leaf surface, capable of assimilating 
food, is a very important part of a green cutting, because 
the stem is less abundantly supplied with reserve food 
during the growth period than during the dormant period 
(185). 

Since the presence of leaf surface upon the cutting 
greatly promotes transpiration (75), propagation from green 
cuttings is scarcely practicable in the open air. The cold- 
frame, hotbed or propagating bed is essential to furnish 
the needed conditions of humidity and temperature. Bot- 
tom heat, with a comparatively low atmospheric tempera- 
ture, is especially important with green cuttings, in order 
that the food assimilated in the leaves may be devoted to 
the formation of roots. A small leaf surface on the cutting 
is generally preferable to a larger one; in man} 7 plants, a 
portion of a single leaf is sufficient. The leaf surface on 
the cutting should in no case be permitted to wilt, hence 
cuttings should generally be sprinkled with water as soon 
as made. 

3?S. Especial Care is Necessary in Propagating 
plants from Green Cuttings. In planting the cuttings, the 
material of the propagating bed should be put in close 
contact with the stems, and no leaves of the cuttings should 
be covered. Since roots cannot grow without oxygen, the 
bed must not be so freely watered as to exclude all air from 

* Asparagus medeloides. 



200 



Principles of Plant Culture. 



it. Transpiration should be reduced b} r sheltering the cut- 
tings from the direct rays of the sun. Movable screens 
placed over the bed during sunshine, and removed at other 
times, are preferable to whitening the glass, as the latter 
causes too much shade when the sun is not shining. 

Damping off, a much-dreaded disease causing cuttings to 
rot at the surface of the bed, is promoted by excessive heat, 
over-watering, or insufficient light or air; also by decom- 
posing organic matter in the material of the bed. Affected 
plants should be promptl} T removed and the cause of the 
trouble should be sought out and corrected. 

879. Green Cuttings should be Potted as Soon as 
Roots are formed, which may be detected by their foliage 
assuming a bright green color. They should first be placed 
in small pots, and, until they have commenced growth in 
these, should be treated precisely as before the} T were potted. 
Propagation by green cuttings includes three divisions, of 
which the requirements differ in some respects, viz., by cut- 
tings of herbaceous plants, of woody plants (381), and of the 
leaf, or parts of the leaf, (leaf cuttings) (382). 

380. How to Make 
Green Cuttings of 
Herbaceous Plants. 
Roots develop most 
readily from the 
younger and more suc- 
culent parts of the 
stem, in herbaceous 
plants. Bend the shoot 
near its terminus in 
the form of a U, and 
then press the parts 
If the stem breaks squarely off, with a snap, it is 




Fig. 100. Fig. 101. 

Fig. 100. Cutting of chrysanthemum. 
Fig. 101. Rooted cutting of coleus. (Both after 
Bailey). 

together. 



Propagation by Cuttings. 201 

in the proper condition to root promptly, but if it bends 
without breaking, it has become too hard. Cutting below 
a node is not essential to the formation of roots * in herb- 
aceous plants. 

While the propagating house or hotbed is necessar} T to the 
extensive multiplication of herbaceous plants by green cut- 
tings, the amateur ma} T readily propagate a limited number 
of plants by the so-called " saucer system," during the tem- 
perate months of the year. The cuttings ma} r be placed in 
glazed saucers containing sand, that should be kept saturated 
with water. The saucers may be placed in any warm, well- 
lighted place, as the window of a living room. The stems 
of the cuttings being in this case in direct contact with the 
water in the bottom of the saucer, require less shading than 
cuttings in the propagating bed. 

381. How to Make Green Cuttings of Woody Plants. 

Cuttings of woody plants are preferably made of harder 
growths than those best suited to herbaceous plants. They 
should be selected from young shoots of medium size, and 
from half-mature wood, and should generally contain from 
two to three nodes, though where the material for cuttings is 
scarce, single buds may be used in man} r plants. The base 
of the cutting is preferably cut shortty below a node, but 
this is not essential in all plants. 

A mild bottom heat is of advantage in this kind of propa- 
gation, though it is sometimes carried on during the summer 
months without artificial heat. 

382. Propagation by Leaf Cuttings. A considerable 
number of plants, including the bryophyllum, begonia, ges- 

* la a few plants, as the dahlia, the presence of a dormant bud at the crown is 

essential to the development of the stem the succeeding year. Cuttings of such 

plants should therefore be made below a node, if the roots are desired for future 

use. 

13 



202 Principles of Plant Culture. 

nera and others, readily develop growing points of the stem 
and roots upon their leaves, a fact often turned to account 
in propagating these plants. Well-matured leaves, with the 
principal nerves cut across on the under side, are held in 
close contact with the surface of the propagating bed by 
pegging, or by light weights, or the leaf may be cut into 
pieces, which may be placed in the propagating bed and 
treated as ordinary green cuttings. 




'f'VA"i 



r 

Fig. 102. Leaf of begonia on surface of propagating bed, giving rise to young 
plants. (After Bailey.) 

The leaves of the bryophyllum form rootlets and buds 
from the notches on their borders wherever these chance ta 
come in contact with a moist medium. 

b — Propagation by Grafting . 

383. Grafting consists in placing together two portions 
of a plant, or of different plants, containing living cambium 
tissue (69), in such a way that their cambium parts are main- 
tained in intimate contact. If the operation is successful, 
growth will firmly unite the two parts (70), and plant pro- 
cesses will go on much the same as if the parts had never 
been separated. The union usually takes place most rapidly 
when the cambium cells are in the state of most rapid divis- 
ion, i. e., when growth is most vigorous. 



Propagation by Grafting. 203 

The more intimate the contact of the cambium of the parts 
brought together, and the less injury their cells sustain in 
adjusting them, the more likely are they to unite. 

Although the tissues of two plants of differing character 
often unite in grafting, each of the united parts almost 
always retains its individual character. For example, if 
one or more buds of the Ben Davis apple are caused to unite 
by grafting with the stem of a Baldwin apple, the parts that 
grow thereafter from the Ben Davis buds, though nourished 
by sap that has passed through the Baldwin roots and stem, 
with rare exceptions, continue to be Ben Davis, while the 
parts that grow from the Baldwin stock continue to be Bald- 
win. To this fact is due the chief value of grafting, viz. r 
it enables us to change the character of a plant (384a). 

The plant that it is desired to change by grafting is called 
the stock, and the part designed to be united to the stock is 
called the graft, cion (scion) (386) Or hud (394). 

384. Objects of Grafting. Grafting enables us 

a — To change a plant of an undesirable variety into one 
or more desirable ones; 

b — To preserve and multiply plants of varieties that can- 
not be preserved or multiplied by growing them from their 
seeds; 

c — To hasten the flowering or fruiting of seedlings grown 
with a view to improving varieties; 

d — To change the size of trees, as to make them more 
dwarf ; 

e — To restore lost or defective branches; 

f — To adapt varieties to special soils; 

g — To save girdled trees. 

385. The Plants that Unite by Grafting. Plants of 
different varieties of the same species (21) almost always 



204 Principles of Plant Culture. 

unite by grafting. Examples, the Ben Davis and Baldwin 
apples, the Bartlett and Seckel pears. 

Plants of different species of the same genus (21) often 
unite by grafting. Examples, the peach unites with the 
plum; many pears unite with the quince; the tomato unites 
with the potato. 

Plants of different genera in the same family or order (21) 
sometimes unite by grafting. Examples, the chestnut unites 
with the oak; the pear unites with the thorn, etc. 

The apparent resemblance of two plants of different 
species is not always evidence that they will unite by graft- 
ing; e. g., the peach and apricot, though resembling each 
other in many respects, do not readily unite by grafting, but 
both unite freely when worked upon the plum, though the 
latter apparently differs from both the peach and apricot 
more than these differ from each other. 

Many plants unite freely when grafted in one direction, 
that fail to unite when worked in the opposite direction: e. 
g., many cultivated cherries unite freely when worked upon 
the mahaleb cherry, while the latter fails to unite when 
worked upon any of the cultivated cherries; many pears 
unite freely when grafted upon the quince, but the quince 
does not freely unite when worked upon the pear. The 
only sure way of determining what species may be united 
by grafting is by trial. 

Three principal kinds of grafting are in use, viz., cion 
grafting, budding (394) and approach grafting (399). 

386. Cion Grafting is used in grafting on roots (root- 
drafting (391)), and very often in grafting on the stem, espe- 
cially on large trees. The cion (scion) is a short section of 
the dormant stem, of the variety it is desired to propagate. 



Propagation by Grafting. 205 

It should generally be of the preceding season's growth, and 
should always contain one or more healthy leaf-buds.* Cions 
are usually cut in autumn, or during mild weather 
in winter or early spring, and are commonly stored 
in moist sawdust, moss or leaves, in a cool cellar, until 
needed for use. In climates of severe winters, they should 
always be cut in autumn. Cions should not be kept so 
moist as to cause swelling of the buds or the formation of 
callus (73), nor so dry as to cause shriveling. 

In cion grafting, the proximal (116) end of the cion is 
joined to the distal end of the stock in such a way that the 
cambium layers of the two coincide in at least one place. 
Cion grafting in the open air is usually most successful 
when performed just before or during the resumption of 
active growth in spring, and the cion is thought to unite 
more readily if in a slightly more dormant condition than 
the stock, possibly owing to its more ready absorption of 
water when in this state. 

The joints made in cion grafting are general^ coated with 
a thin layer of grafting -wax to prevent evaporation and to 
keep out water. Sometimes the whole exposed part of the 
cioju is waxed. 

387. To Make Grafting=Wax for cleft-grafting (392) r 
melt together four parts, by weight, of unbleached rosin, two 
parts of beeswax and one part of beef tallow; pour into 
water, and when sufficiently cool, work with the hands until 
the mass assumes the color of manilla paper; roll into sticks 
and wrap with parafined paper to prevent sticking. Several 
other formulas are in use. 



* Flower-buds are occasionally used, but except in special cases, they should be 
avoided. 



206 Principles of Plant Culture. 

For whip-grafting (390), where waxed cord, cloth or paper 
is used, the beeswax may be omitted from the above for- 
mula, or one-half more tallow may be added. 

388. Grafting Cord is made by soaking balls of com- 
mon wrapping twine in melted grafting wax. 

389. Grafting Paper is made by painting thin manilla 
wrapping paper with melted grafting-wax. For painting, 
the paper is preferably spread out on a board of the exact 
size of the sheet; to prevent too rapid cooling of the wax 
the board should be heated. The wax should be heated hot 
enough to spread easily, but not so hot that it is absorbed 
\>y the paper. Sometimes very thin muslin or calico is used 
instead of paper. 

Grafting paper and grafting cloth should be stored in a 
cool, moist place; otherwise they soon lose their adhesive- 
ness. 

Many kinds of cion grafting slightl} T differing in details 
have been described, but the more important are whip- 
grafting, cleft-grafting and side- grafting. 

390. In Whip=Grafting (splice-grafting, tongue-graft- 
ing) the cion and stock, which should be of about the same 
thickness, are both cut off with a sloping cut, about an inch 
long, after which a tongue is formed on each by splitting 
the wood longitudinally a short distance (Figs. 106, 107). 

In joining, the tongue of the cion is inserted into the 
split of the stock, so that the cambium line of the cion and 
stock coincide on one edge, and the two are crowded to- 
gether with considerable force, after which the joint is 
wrapped with a narrow strip of grafting paper or grafting 
cloth (389), or wound with grafting cord (388). Sometimes 
the joints are simply tied with unwaxed cord. 



Propagation by Grafting. 207 

Whip-grafting is generally used when the stock is little 
if any thicker than the cion. It is much used by nursery- 
men in certain localities, in grafting the apple and some 
other fruits, upon roots (root-grafting) (391). 

Whip-grafting is also considerably used in some climates of 
severe winters, in top-grafting or " top-working " apple trees 
in the nursery, in order to give certain slightly-tender vari- 
eties the benefit of a specially hardy stock. This grafting 
is performed on two- or three- year-old trees, that have been 
grown from root grafts. The trunk is cut off at the height 
it is desired to form the head of the tree, and a cion of the 
variety it is desired to propagate is inserted; or several 
cions are inserted in as many branches. The latter method, 
while more expensive, has the advantage of giving to the 
top-grafted trees the branch formation of the stock, which 
is sometimes important. 

As growth starts on top- grafted trees, shoots that push 
out from the stock should be rubbed off to prevent them 
from robbing the cions of nourishment. 

391. Root=Qrafting is generally performed in winter, 
and in-doors. The stocks are small trees, grown one or two 
years from seed (seedlings). These are dug in autumn, and 
stored as recommended for cions (386). When ready for 
grafting, the roots are washed, and trimmed b}' cutting off 
the branch roots, after which the stem is cut off at the crown, 
and the distal end of the root is shaped as directed 
above (390). It is then cut off two or three inches down, 
and the remaining root, if sufficiently thick, is shaped for 
another stock. Three or four stocks are sometimes made 
from a single root. As a rule, the stocks should not be less 
than three-sixteenths inch in diameter, nor less than two 
inches long. 



208 



Principles of Plant Culture. 



Some nurserymen prefer to make but a single stock from 
one root (* whole-root " grafts). 






Fig. 103. Fig. 104. Fig. 105. Fig. 106. Fig. 107. Fig. 108. Fig. 109. 

Fig. 103. Grafting knife. This should be of excellent steel. The curved blade 
is not essential. 

Fig. 104. Cion used for whip-, root- or cleft-grafting, one-fourth natural size. 

Fig. 105. Seedling root, used in root-grafting, one-fourth natural size. 

Fig. 106. Cion shaped ready for insertion. The split should be in the center of 
the wood, rather than near one side, as in the figure; reduced nearly one-half. 

Fig. 107. Portion of seedling root, shaped to receive the cion. 

Fig. 108. The cion and portion of root, put together. 

Fig. 109. The same as Fig. 108, wrapped with grafting paper. 



Pro-pagation by Grafting. 209 

For root-grafts, the cions are cut from two to six inches 
long by different nurserymen. In climates subject to drought 
in summer and severe freezing in winter, the longer cions 
are more satisfactory, as they permit the stock to be cov- 
ered to a greater depth, and encourage rooting from the 
cion, which is regarded as an advantage. 

Root-grafts should be stored until time for planting out r 
as directed for cions (386). 




Fig. 110. Shaping the cions for root-grafting. A, making the "long cut"* 
B, cutting the " tongue " ; C, cutting off the cion. These positions, and the move- 
ments they indicate, are adapted to rapid work. 

392. CIeft=G rafting is generally employed when the 
stock is considerably thicker than the cion. The cut-off end 
of the stock is split across its center, with a grafting chizel 
(Fig. Ill), and the proximal end of the cion, which is cut 
wedge-shaped, and a little thicker on one edge than the other, 
is so inserted into the cleft that the cambium of the thicker 
edge of the cion forms a line with the cambium of the stock 
(Figs. 112, 113, 114). Success is promoted if the wedge- 
shaped portion of the cion contains a bud on its thicker 
edge. When the stock exceeds an inch in thickness, two 
cions are usually inserted (Fig. 113), to increase the chances of 
success. The elasticity of the stock should exert sufficient 
pressure to maintain very close contact between it and the 
cion. If it does not do this, it should be tightly bound with 
cord or raffia (393). The cion should contain at least one 



2IO 



Principles of Plant Culture. 







bud beyond the end of the stock. The wedge-shaped cut is 
usually madeQabout one inch long, and the cion should be 

inserted into the cleft as far as the 

length of the wedge, after which 

all the wounded surfaces, including 

the distal end of the cion, should 

be coated with grafting-wax (387). 

Cleft-grafting is most used in 

top- grafting old trees. Four to six 

of the main branches, located as 

nearly equi-distant as 

possible (Fig. 115), are 

selected for grafting, 

and it is desirable to 

graft these rather near 

Fig. 111. Grafting 
chizel, for making the 
cleft in cleft-grafting. 
The point at the right 
is for holding the cleft 
open during insertion 
of cions. The projec- 
tion above is for driv- 
ing the point in or out, 
one-fifth natural size. 

to the top of the 
trunk. 

Branches ex- 
ceeding three in- 
ches in diameter 
should not be 





G>oA 



Fig. 112. Fig. 113 Fig. 114. 

Fig. 112. Cion shaped ready for insertion in cleft. 
(After Bailey). 

Fig. 113. Cions inserted in cleft, ready for waxing. 

Fig. 114. Cross section of Fig. 113. (After Maynard). 
C, cambium layer of stock ; C, cambium layer of cion. 
The cambium layers of the outer edge of the cion should 
form a continuous line with that of the stock. The cion 
is made a little thinner at its inner edge to permit the 
pressure of the stock to be exerted at the outer edge. 



grafted, as a rule. 
About half of the top of the tree should be cut away just 
before the grafting, leaving some branches to utilize a part 
of the sap. The more or less horizontal branches should 
generally be selected for grafting, and in these, the cleft 



Propagation by Grafting. 



211 



should be made horizontally, to give the two cions inserted 
an equal opportunity for growth. Should both the cions in 

a branch grow, the weaker one 
should be pruned off later. As 
growth starts, shoots from the 
stock must be rubbed off (390). 




Fig. 115. Branches of tree to 
he top-grafted, as seen from 
above, showing where to insert 
the cions to make a well-formed 
head, i. e., at the dotted lines. 




Fig. 116. Cleft-graft in trunk of old grape 
vine. The cions are usually inserted below the 
surface of tbe ground, and no wax is used. 
(After Bailey). 



The spring following the top-grafting, all or a part of the 
branches left on the stock at grafting should be pruned off 
to encourage growth of the grafts. If the tree 
is large, and of a vigorous variety, it is wise 
to leave a part of these branches until the 
second spring. 

393. Side=Grafting, is chiefly practiced 
with plants in leaf, under glass. The cion is 
joined at the side of the stock, which is usually 
not cut off, and is secured in place by wrap- 
ping tightlj T with bast* or raffia. Three 
slightry different methods are in use. 
a — A shaving of bark, sufficiently thick to reach into the 
cambium layer, is removed from the side of the stock by 

* Bast is the fibrous inner bark of the bass-wood or linden tree, (Tilia). It was 
formerly much used for tying grafts and buds, but has been largely supplanted by 
raffia, which comes from a palm of the genus Rapbia. Raffia may be purchased of 
dealers in nursery supplies. 




Fig. 117. Side- 
graft inserted, 
ready for tying. 



212 Principles of Plant Culture. 

making a long vertical cut and a short transverse cut at 
the base, and to this cut surface the cion is carefully fitted, 
and bound with raffia. This method is called veneer -grafting. 

b — A sloping cut is made rather deeply into the sapwood 
of the stock, into which the cion, after being tapered at its 
base to the form of a wedge, is inserted (Fig. 117), and the 
parts are then held closely together by binding with raffia. 
This method is generally employed in herbaceous grafting, as 
with the potato, tomato etc. It is also much used in grafting 
evergreens under glass, and occasionally in grafting out- 
door nursery trees. In the latter case, a coating of grafting 
wax is usually substituted for the tying. 

c — A short, transverse incision is made, and immediately 
below this, a somewhat longer, vertical cut; the two cuts, 
which are just deep enough to reach through the bark, 
forming a T (Fig. 120). The cion is then cut off with a long, 
sloping cut, and the point inserted, the cut surface inward, 
beneath the two lips of bark formed by the T-cut, after which 
the cion is crowded downward until its cut surface is in con- 
tact with the cambium layer of the stock, when the juncture . 
is bound with raffia. 

394. Budding is now extensively employed in prop- 
agating fruit trees, roses and the varieties of deciduous, or- 
namental trees and shrubs. A (usually dormant) leaf-bud, 
with a small portion of surrounding bark (Fig. 119), is 
placed in contact with the cambium layer of the stock. 
Budding may be successful whenever the cells of the cam- 
bium layer are in a state of active division, as indicated by 
the ready separation of the bark from the wood. In climates 
having severe winters, budding is most satisfactory when 
performed near the latter end of the growing season, and 
with fully-matured buds, in order that the buds may not 



Propagation by Grafting. 213 

expand until the following spring; thus the shoots growing 
from the inserted bud will have the whole season for growth 
and maturity. With plants that unite freety, and with the 
stock in the proper condition, 

395. Success in Budding Depends Upon 

a — Afresh condition of the buds, which must not be in the 
least shriveled from diyness. 

b — The proper removal and insertion of the bud, of which the 
growing point (67) must not be injured. If this comas out, 
leaving the bud-scales partially hollow, the bud will not 
grow, if inserted upon the stock. The bud should be in- 
serted promptly to avoid loss of moisture. 

c — The proper wrapping of the wounded bark, to prevent 
evaporation and exclude moisture. The ligature should not 
cover the bud. 

d — The removal of the ligature after the union, to permit 
expansion of the stock. 

e — The cutting off the stock just bej^ond the bud, when 
the latter commences growth, to stimulate its development. 

Two methods of budding are in use, viz., T- or shield-bud- 
ding and ring- or annular-budding. 

396. In T=Budding, which is much the more common 
and the more expeditious method, a short shaving, contain- 
ing a hard and plump bud and cut deep enough to reach 
through the cambium (Fig. 119), is inserted beneath the 
bark of the cion, as described for side-grafting (393c). 

The buds, which should be plump and mature, and of the 
variety it is desired to propagate, are taken from shoots of 
the current season's growth. These shoots (" bud sticks ") 
(Fig. 118) should be cut the day the buds are to be inserted, 
and should be trimmed at once, and rolled in damp cloth, to 
prevent loss of moisture. The trimming consists in cutting 



214 



Principles of Plant Culture. 



off the leaves, saving a bit of the leaf stem (petiole) to serve 
as a handle while inserting the buds. The stocks, whether 
grown from seeds or from cuttings, are usually of one 
or two season's growth. The lower branches of the stock 
are cut off up to three inches or more from the 
ground, and a smooth place is selected for the bud, 
usually on the side least exposed to the sun's rays. 
With the budding knife, a T-shaped cut is made on 
the stock (393c) about two inches 
above the ground. A bud is then 
cut from the bud stick, by 
inserting the blade of the 
budding knife about a fourth 
of an inch below the bud, at 
such an angle that the back 
of the blade nearly touches 
the bark of the stock. The 
blade is passed just 
behind the bud, 
touching the wood, 
but not removing 
much of it, and 
then turned a lit- 
tle, running out 

Fig. 118. Shoot containing buds. The white spaces about a fourth of 
about the buds indicate the amount of bark to be cut an jjjgjj above the 
off with the bud. The shoot is inverted for cutting the «i-A. 

buds. bud (Fig. 119). 

Fig. 119. Bud cut off, ready for insertion. Often the knife 

Fig. 120. Bud partially inserted between the lips of 

the stock. does not run out, 

Fig. 121. Bud inserted and tied. (All after Bailey). but ^ bark ig cut 

off square, a quarter of an inch above the bud, as indicated 
in Fig. 118. 




Fig 118. 



Fig. 120. 



FiG. 121. Fig. 119. 



Propagation by Grafting. 



215 



With the spatula of the budding knife (397), the lips of 
bark in the angles of the T-cut are loosened from the wood, 
when the bit of bark bearing the bud is slipped down behind 
them (Fig. 120), with the bud pointing upward, until the top 
end of the bit of bark is just below the horizontal cut of the 
T. Some budders do not use the spatula, but raise the lips 




,-a^dl?P 





Fig. 122. A lesson in budding. The left hand student is cutting a bud; the 
central one is lifting the lips of the bark with the spatula of his budding knife; 
the right hand student is tying the bud. 

of bark with the blade of the budding knife. The center of 
a strip of moistened raffia is then applied to the stock just 
below the inserted bud; the ends of the strip are crossed on 
the opposite side of the stock, brought forward and again 
crossed just above the bud, thus covering the horizontal cut 



2l6 



Principles of Plant Culture. 



of the T. The ends of the raffia are then brought behind 
the stock, tied in a half knot, and drawn moderately tight 
(Fig. 121), pressing the lips down snugly about the bud, 
which now protudes between the lips. 

If the bud " takes," it will grow fast to the stock in a few 
days. The raffia should be taken off in about ten days, by 
cutting it on the back side of the stock, to enable the latter 
to expand by growth. 

397. The Budding Knife should con- 
tain a blade of good steel, shaped as indi- 
cated in Fig. 124, and a round-edged spat- 
ula for lifting the bark. The spatula is 
better placed on the back of the blade, as 
shown in Fig. 125. 

398. Ring Budding is used to some 
extent in the propagation of thick-barked 
plants, as the hickory and magnolia. A 




Fig. 123. Man budding in nursery row. 
(After Bailey). 



Fig. 124. Fig. 125. 
Fig. 124. Budding 
knife with ivory spat- 
ula on the end oppo- 
site the blade. 

Fig. 125. Budding 
knife made from eras- 
ing knife by rounding 
the edge at A. 



section of bark is removed nearly or entirely around the 
stock, and a similar section containing a bud, from the 
variety it is desired to propagate, is fitted to its place and 
snugly bound with raffia. Ring budding is oftener per- 
formed in spring than later in the season. 



Propagation by Graf tin 



g- 



217 



399. Approach Grafting is now seldom employed, ex- 
cept in a few plants that unite poorly by other methods. It 
is only possible between two plants in close pxoximit}', or 
between parts of the same plant, since the graft is not sev- 
ered from the parent until it has united with the stock. 
The plants are nourished b}* their own roots until the union 
takes place. 

Approach grafting is performed during, or just previous 
to, the growing season. The parts are held in contact by 
binding them with raffia; the juncture should also be waxed 
if the work is done in the open air. 

Two methods of approach grafting are in use. 

a. A shaving reaching into the 
cambium layer is removed from 
both stock and graft on the sides 
toward each other (Fig. 125), and 



.-■- / ■' 




— aot- 





Fig. 125. Fig. 126. 

Fig. 125. Two plants "prepared for approach grafting. The cut surfaces a, a, 
are to be placed together and bound. 

Fig. 126. Two plants bound together for approach grafting. (After Bailey). 

the cut surfaces are brought together and closely bound 
14 



218 Principles of Plant Culture. 

until they unite (Fig. 12)1). after which the graft is cut off 
below, and the stock above, the union. 

b. The top of the stock is cut off with a long sloping cut, 
preferably behind the bud, and the cut surface of the re- 
maining part is inserted beneath the bark of the graft, as 
described in side-grafting (393c), except that the T-cut is 
inverted, and the stock is inserted from beneath. 

The graft is cut off below the point of union when the 
parts are fully united. 

In both these methods the graft should be severed gradu- 
ally, to avoid a check to the growth. 

Section II. Transplanting 

The processes treated in this, and the succeeding section, 
may be likened to surgical operations in medicine. If plants 
are less highly organized and possess less of sensibility than 
the higher animals, they are, none the less, living beings. 
Violent operations, if necessar}-, should alwaj^s be performed 
with this truth in mind. Needless injury and careless hand- 
ling in the treatment of /limits arc always to be avoided. 

400. Transplanting consists in lifting a plant from 
the medium in which its roots are established, and in re- 
planting the latter, usually in a different location. Trans- 
planting is a violent operation because the younger roots, 
with their root-hairs that absorb the greater part of the 
water required by the plant (103), are, as a rule, largely 
sacrificed in the lifting process. The water supply, so 
vitally important to the plant (63), is thus greatly curtailed 
until new root-hairs can be formed. 

Vigorous plants are better able, as a rule, to endure trans- 
planting than feebler ones, because the}' can sooner repair 



Transplanting . 219 

the damage done to their roots. It follows that plants en- 
dure transplanting with less facilit} 7 as they advance in age 
beyond the period of greatest vigor (8). 

401. The Most Favorable Time for Transplanting, 

in the case of plants that live more than one 3'ear, is during 
the dormant period, because growth processes are then least 
active, and comparatively little water is needed. In coun- 
tries having mild winters, the most favorable time for 
transplanting is general^ at the beginning of the dormant 
period, provided this comes at a moist season of the year. 
The roots will then have time to slowl} 7 callus over their 
wounds and to form new rootlets, and thus be prepared for 
active growth in spring. But in countries of severe winters, 
where the roots are largely frozen in the soil for two or three 
months during winter, spring is, as a rule, the more favor- 
able; season for transplanting. 

Trees that have been long exposed to cold, drying winds, 
and have thus suffered depletion of water from their buds 
and branches, are better not lifted until the buds begin to 
swell. This is especially true of evergreen trees in severe 
climates. These being always in leaf, require more careful 
treatment than deciduous trees. 

We shall consider transplanting under three divisions, 
viz., a. lifting the plant; b. removing the plant; and c. replant- 
ing the plant. 

A — Lifting the Plant 

402. The object to be attained in this operation should 
be to remove the roots from the soil with the least possible 
damage, consistent with reasonable economy of time and 
labor. Plants in low vigor should receive especial care in this 
respect. Very young plants, as of tobacco, cabbage, lettuce 



220 Principles of Plant Culture. 

etc., grown thickly in the seed-bed, are often pulled from 
the soil with the hands. In this case, the soil of the bed 
should first be saturated with water, in order that the roots 
may be broken as little as possible, and may come up with 
more or less adhering soil. It is generally preferable to 
grow such plants in drills, rather than "broadcast." This 
will enable them to be drawn from the soil with less damage 
to their roots. 

Trees and shrubs sufficiently grown for their final plant- 
ing out should be more carefully handled. If it is neces- 
sary to cut off the main roots, the farther from the trunk 
this is done, the better for the tree, and the spade used 
should be kept as sharp as possible. The roots should not be 
barked, mangled or split by the digging tools, as is so often 
done with nursery stock. When possible, one person should 
lift on the tree or shrub, while another removes the earth 
from about the roots. Tree-digging machines are now much 
used hy the larger nurserymen. 

403. Lifting Large Trees. Trees considerably larger 
than nursery sizes are best lifted when the ground is frozen 
about their roots. A trench may be dug about the tree, 
deep enough to permit the severing of the main roots, before 
the ground freezes, and a hole for the reception of the 
cylinder of earth left within the trench should also be dug 
at the place to which it is desired to remove the tree. This 
cylinder should be large enough so that the tree is left with 
abundant roots, or as large as can be removed with the ap- 
paratus at hand. When the ground is frozen to the proper 
depth, the tree may be tipped over by means of a rope and 
windlass, after which the cylinder of earth inclosing the roots 
may be pried up sufficiently to allow some low vehicle to be 



Transplanting. 221 

placed beneath it. The branches are usually permitted to 
drag upon the ground in removal, as the wounded parts may 
be cut off in the severe pruning necessary in planting large 
trees (410c). 

Large trees may be lifted or lowered to accommodate 
grading. A trench is dug around the tree, leaving a cylin- 
der of earth intact about the roots. Soil is then removed 
from beneath one side of the cylinder, below the roots, and 
a block set under as a fulcrum. The top of the tree is then 
inclined toward the fulcrum by means of a rope, until the 
roots are lifted on the opposite side. If the tree is to be 
raised, soil is packed under the elevated roots, after which 
the top is tilted in the opposite direction, until the roots are 
lifted on the fulcrum side, when soil is placed under as be- 
fore. This process is repeated until the tree has been lifted 
to the desired height. If the tree is to be lowered, earth is 
removed at each tilt. 

40-1. Sacking the Earth=Inclosed Roots is practiced 
in lifting and removing orange trees in California, and might 
doubtless be profitabl}- emplo3 T ed with other evergreens. A 
rather deep trench is dug at one side of the trees, and from 
this trench, the deeper roots are severed. The top earth is 
then removed down to the first lateral roots, when all the 
remaining large roots are severed at some distance from the 
trunk. The tree is next carefully lifted out, with the C}~lin- 
der of earth attached to its roots, and set on a piece of bur- 
lap or matting, which is folded about the earth c} T linder and 
well tied. 

B — Kemoving the Plant 

Plants with their roots out of the soil should be carefully 
protected from mechanical injur} 7 , from drying and from 



222 Principles of Plant Culture. 

freezing. To insure such protection, plants to be trans- 
ported an} T considerable distance should be packed. 

405. Plants Packed for Transportation should be 
inclosed throughout, and the roots should be in close con- 
tact with some moist material, preferably bog moss; straw 
is often used for this purpose, and answers well for packing 
about the trunks and branches of trees, but it is inferior to 
moss for inclosing roots as it is more liable to heat, and 
does not so well retain moisture. 

Herbaceous plants, as of the strawberry, cabbage, sweet 
potato etc., may be packed in layers separated with moss, 
as follows: Over the bottom of a box, of which the width is 
about double the length of the plants to be packed, and 
which has slatted sides, place a thin layer of damp (not wet) 
moss, and over this, place a la} r er formed of a double row 
of the plants, with their roots at the center, overlapping a 
little, and the tops toward the sides of the box. Then put 
another layer of moss and another layer of plants, and so 
on until the box is full, or the desired quantity is packed. 
The thickness of the layers will depend upon the time of 
year, the temperature, the distance to be transported and 
the kind of plants. The warmer the weather, the thinner 
should be the layers of plants, as a rule. When the top of 
the box is put on, the contents should be pressed sufficiently 
to prevent the plants from shaking out of place. 

406. Puddling the Roots of Trees, i. e., dipping them 
in a paste of soil and water, is much practiced by nursery- 
men, and tends to prevent them from drying. The paste 
should be made with rather light, loamy soil and of the 
consistenc} T of cream. 



Tra nsplanting. 223 

407. Trees are commonl} T Bundled for Transportation 

to economize space. For this purpose, a device resembling 
a sawbuck, with the arms cushioned with burlap or carpet- 
ing is very convenient. The trees are laid between the 
arms, with the roots placed evenly at one end. The stems 
are then drawn snugly together with a broad strap, after 
which they are bound with soft cord, or with young and 
slender shoots of the osier willow.* After bundling, the 
spaces between the roots should be filled with damp moss, 
and the whole mass of roots surrounded with the same ma- 
terial. If the distance to be transported is short, the mossed 
roots may be sewed up in burlap or matting and the tops 
may be tied up in straight straw, or the whole bundle may 
be inclosed in burlap. If the distance is long, the bundles 
should be boxed, to more effectually prevent the trees from 
damage. The bundles may be packed very closely in the 
box without injury, provided they nowhere come in direct 
contact with it. Bundles or boxed trees, that cannot be 
shipped at once, should be stored in a cool, damp place. 

408. Unpacking and Heeling=In. Packed plants 
should generally be removed from their package as soon as 
they reach their destination. If they cannot be replanted 
immediately, they should be heeled- in. This consists in re- 
moving them from their bundles, and temporarily planting 
their roots in soil (Fig. 129). The roots should be well cov- 
ered, and if at a dry season, they should also be mulched. 
To avoid mixing varieties, a separate row should be made 
of each sort. 

Nursery trees that cannot be packed for shipment at the 
proper time, are often lifted and heeled-in, to retard the 
starting of their buds. 



* Salix viminalis. 



224 Principles of Plant Culture. 

C — Keplanting 

409. Preparation of the Plant, a — Washing the roots. 
The - : puddled " (406) roots of nursery trees are sometimes 
found inclosed, at unpacking, in a mass of mud that is so 
compact as to largely exclude the air (Fig. 130). The roots 
of such trees should be washed clean before replanting (Fig. 
131). 




Fig. 129. Nursery trees heeled-in to prevent drying. A, a short row of trees 
with only the roots covered. B, a row with their tops bent down and covered with 
earth at C. (After Green). Sometimes the whole tops are covered. Trees should 
not be heeled-in in the bundles. 

b — Trimming the roots. The roots of trees that were 
broken or mangled in the lifting or 
transportation, should be cut back with 
a sharp knife to sound wood. 

Fibrous rooted plants, as the straw- 
berry, are much more readil} 7 planted 
when the roots are trimmed, as shown 
in Fig. 29, (p. 71). 

c — Reducinq the top. The buds of 

Fig. 130. Fig. 131. , 

Fig. 130. Puddled roots trees and shrubs should generally be 
of nursery tree. reduced in number, at replanting, to 

Fig. 131. Thesame L ° 

washed, ready for plant- correspond with the destruction of the 
ing younger roots during the lifting process, 

otherwise the water supplied by the roots may be insuffici- 




Transplanting'. 225 

ent to open the buds (63). This is best accomplished by 
thinning out, and cutting back the branches. As a rule, it 
is better to reduce the top rather sparing!}- at replanting, 
with the expectation of cutting it back further if the buds 
do not promptly open at the proper time. The branches 
that can best be spared should be removed (420). Failure 
to properly reduce the top is a frequent cause of loss of 
vigor, or death in transplanted trees. 

Small plants, in leaf, as of the strawbeny, cabbage etc., 
usually endure transplanting better if their larger leaves 
are removed at replanting. 

d — Wetting the roots just before replanting them is quite 
important, as it favors intimate contact with the soil par- 
ticles. 

Plants that have suffered from loss of moisture in transit 
should have their roots soaked in clean water for a few 
hours before replanting. Deciduous trees of which the bark 
is considerably shriveled ma} T often be saved, if the center 
of the buds is still fresh, by burying them in moist earth 
until the bark resumes its plumpness. 

410. Replanting the Roots. The object to be attained 
in this operation is to place moist and well-aerated soil in 
very close contact with all of the roots of the plant. The roots 
should also be placed at about the same depth, and in nearly 
the same position that the} T grew before the removal. The 
first requirement is most important, but the other two should 
not be ignored. 

Fig. 132 shows the roots of a tree properly planted. The 
hole was dug sufficiently large so that the roots were readily 
placed in it without crowding, and the soil was so well 
worked in among the roots that it comes in contact with 
their whole surface. 



226 



Pri7icifles of Plant Culture. 



Fig. 133 shows the roots of the same tree improperly 
planted. The hole was dug so small that the roots were 





Fig. 132. 
Fig. 132. Roots of tree properly planted. 
Fig. 133. Same improperly planted. 



Fig. 133. 




necessarily crowed out of their natural position, and the 

earth was 
thrown in so 
loosely that it 



comes in con- 
tact with only 
a part of the 
root surface. 
Distortion of 

Fig. 134. Strawberry plant too deeply planted. 
Fig. 135. Same planted too shallow. 

the roots of trees and shrubs at plant- 
ing probably causes abnormal root 
growths that seriously injure their 
vigor. 

In planting trees of which the roots 
are not alread}' inclosed in soil (403), 
the hands should be freely used to 
bring the soil in contact with the 

Fig. 136. Strawberry plant 

whole root surface, and the earth planted properly. 




Transplanting. 



227 



should be moderately packed about the roots with the feet, 
or otherwise. 

If the soil is dry, it is probably better to moisten it before 
placing it about the roots, rather than after, as we have then 
a better opportunity to judge of the quantity of water re- 
quired, and the soil is less likely to settle awa} 7 from the roots. 

Trees of considerable size 
should generally be staked or 
otherwise supported after 
planting, to prevent shaking 
by wind. Surrounding the 
trunk with poor-conducting 
material as hay, straw or can- 
vas, tends to prevent damage 
from sun-scald (186), to which 
recently-transplanted trees are 
especially liable (Fig. 137); as 
the evaporation stream (78) is 
much reduced, the bark tends 
to become unduly heated. 

411. Devices for Trans= 
planting. With young trees 
and plants, that possess abun- 

Fig. 137. Large transplanted tree 
dant Vigor, rapidity Of planting WOU nd with hay rope, and supp >rted by 

is often of greater importance wires ' 

than the observance of precise rules. In this case, that 
method is best which secures a given number of trans- 
planted and vigorousl} T -growing plants at the least cost. 
The transplanting devices shown in Figs. 138-141, inclusive, 
aid greatly in accomplishing this end. 

The dibber (Fig. 138) is perhaps, aside from the spade, the 
most valuable single tool for transplanting. It is used for 




228 



Principles of Plant Culture. 



opening the hole to receive the roots of small plants, as of 
cabbage, celery, onions etc., and for pressing the earth about 
the roots. It answers equally well for planting cuttings and 
root grafts. The manner of using it appears in Figs. 142 
and 143. 

Fig. 139 shows a very convenient tool for 
planting root grafts and cuttings. It consists 
of six steel dibbers, attached in a line to a piece 
of scantling, at the distance apart at which the 
plants or cuttings are to be planted, with a 
handle affixed above. In using this tool, the 
operator crowds the dibbers into the soil with 

3 the foot, guided 





by a line 




Fig. 138. Fig. 139. Fig. 140. 

Fig. 138. Flat steel dibber, (one-third natural size). 

Fig. 139. Tool for planting root grafts and cuttings, (much reduced). 

Fig. 140. Eichards' transplanting tools, made by F. Kicbards, Freeport, N. Y. 

then moves the frame to and fro until the holes are suffici- 
ently opened, when he withdraws the dibbers by lifting the 
frame, and passes on to repeat the operation. A planter 
follows inserting the grafts or cuttings, and crowding earth 
about them with the ordinary dibber. 

Fig. 140 shows a set of transplanting tools, useful in 
removing a limited number of plants that are not close ry 



Tra nsfla n t ing-. 



229 



crowded and that need to be carried but a short distance. 
They are especially useful for transplanting strawberry 
plants during summer and autumn. These tools, and also 

the Baldridge transplanter, en- 
able the plant to be readily lift- 
ed with a cylinder of earth and 
replanted in a hole just large 
enough to receive the latter. 

Fig. 141 shows a successful 
machine for planting tobacco, 
cabbage, strawberry and other 
low, herbaceous plants. It 
plants these as rapidly as two 

Fig. 141. Bemis Transplanter, made 
by Fuller & Johnson Manufacturing boys Can deliver them to it in 
Co., Madison, Wis. ,, ... -, ,, 

the proper position, and at the 
same time, waters the soil about the roots. 






Fig. 142. Fig. 143. 

Planting cabbage plants with the dibber. 
Fig. 142. Inserting roots in the hole opened by dibber. 
Fig. 143. Pressing earth about roots with the dibber. 

412. Potting and Shifting. Potting is the act of 
planting plants in greenhouse pots. 

The pots should be clean, and are usualy dipped in water 
before receiving the plants, until they have absorbed as 



2 3 



Principles of Plant Culture. 



much of the liquid as the} T will take without leaving an} r 
upon the surface. Rooted cuttings are usually potted in 
pots one and one-half or two inches in diameter, and the 
plants are changed to larger pots (shifted) as the roots re- 
quire more room. Pots three inches or more in diameter 
are commonly supplied with drainage by filling the pot one- 
third full or less with pieces of broken pots (potsherds), and 





Fig. 144. Fig. 145. 

Rapid method of planting strawberry plants with spade. 
Fig. 144. One man opens the hole by inserting the spade, back side forward, 
and crowding it toward him. The other inserts the plant, taking care to spread 
out the roots well. 

Fig. 145. The man withdraws the spade and crowds the earth closely about the 
routs of the plant with his foot. 

these are often covered with a little sphagnum moss before 
putting in the soil. The soil used for potting should be of 
a sort that does not harden, " bake," on drying, and should 
generally be liberally supplied with plant food. Decayed 
sods from an old pasture, leaf mold, decomposed manure, 
and sand, the whole sifted and mixed, form a good potting 



Transplanting. 



231 



soil. The proportions of the different ingredients used vary 
with different plants. The soil should be moderately moist, 
and should be closely pressed about the roots. The details 
of potting are shown in Figs. 146 to 149, 

Shifting is the changing of a plant from one pot to an- 
other, usually a larger one. Plants in small pots are usuall} 7 
shifted as often as their roots begin to crowd, and the shift- 





Fig. 146. Fig. 147. 

Fig. 146. The workman takes a pot in his left hand, and at the same time a 
handful of potting soil in the right hand. 

Fig. 147. He places the soil in the pot, pressing it against one side with the 
right hand, while he picks up a plant with the left hand. 

ing is continued as long as further growth is desired. When 
bloom is desired, the pots are permitted to become filled 
with roots (136). 

The pots into which plants are to be shifted should be pre- 
pared as directed for potting. A little potting soil is placed 
in the bottom of the pot, or over the drainage material, 
after which the plant to be shifted is tipped out of its pot, 
hj inverting the latter, placing the hand upon the surface of 



2 3 2 



Principles of Plant Culture. 



the soil, to support it, and tapping the rim of the pot gently 
upon the edge of the potting bench. 

[f the soil is iii proper condition, it will readily slip out 
of the pot intact, after which it should In; placed in the 
ciMitcr of the new pot and the space about it filled with pot- 
ting soil moderately pressed down. The roots of woody 
plants should not be covered deeper than they grew before 
the shifting. 




im<.. i is Fig. 149. 

Ki^- its. Placing the roots of the plant against the soil in the pot with the 
lefl band, be takes another handful of soil with the rigbl band. 

Fig. 1 19, He in is the remaining spaces in the pot with soil and presses it down 
with the thumbs, tapping the pot gently upon the beneb In the meantime, 

I) — APTBE CABE OF Transplanted Stock 

\ l!{. Mulching (233) the soil about transplanted plants 
is very important in Localities subject to drought. As a rule, 
it is wise to apply the mulch immediately after transplant- 
ing, but with trees transplanted very early in spring, it is 
better to defer mulchtng until the soil becomes sufficiently 
warm to promote root absorption (102). 



Transplant in 



£• 



233 



Watering recently-transplanted plants requires discretion. 
As a rule, mulching is preferable to watering, but if mulch- 
ing proves insufficient, watering is the last resort. In this 
case, the soil about the roots should be saturated with water, 
and should not be permitted to become dry again until 
growth starts. A hole may be made in the soil about the 
roots and kept filled with water until the liquid ceases to 
soak away rapidly, after which it should be occasionally 
filled until growth commences. 




Fig. 

filled to 
the plan 

Fig. 

Fig. 
the soil, 



Fig. 150. Fio. 151. Fig, 152. 

150. A poorly- polled plant. No provision is made for drainage; the pot is 
the top with soil, leaving no space to receive the water; and the stem of 
t is QOt :it the (•■liter of I be DOt. 

151. A well-potted plant. A, potsherds; B, moss. 

152. A poorly-shifted plant. C, open spaces, due to insufficient pressing of 



414. Shading plants transplanted in leaf, until the 
roots resume activity, is important (2!'>(>). Evergreen trees 
and shrubs may often be shaded with barrels or boxes, or 
with boughs from other evergreen trees. 

415. Tardy Starting into Growth after transplanting 
is usually evidence that the roots are not supplying suf- 
ficient water. In such cases, if other precautions have been 
observed, it is well to further reduce the top. Plants in 

this condition may sometimes be saved, when other means 
15 



234 Principles of Plant Culture, 

seem likely to fail, by wrapping the stem in oiled- or rubber 
cloth to check loss of moisture, or with straw or moss which 
ma} T be wet frequently till growth starts. 

Flower-buds should generally be removed from recently- 
transplanted plants (140). 

Section III. Pruning 

4:16. Pruning is the removal of a part of a plant, in 
order that the remainder may better serve our purpose. 

The parts of plants, being less highly specialized than 
those of animals, ma} r be removed with less damage to the 
individual than is possible with animals, except in the lowest 
types. 

The word pruning, as common^ used, applies chiefly to 
the removal of parts of woody plants with the knife, shears 
or saw, but the operations defined below properly come under 
the same head. 

a Pinching is the removal of the undeveloped nodes at 

the terminus of growing shoots, with the thumb and finger, 
to check growth. 

b — Trimming or dressing, when applied to young nur- 
sery stock, is the shortening of both roots and stem, prepar- 
atory to planting in nursery rows. The roots are shortened 
to facilitate planting, and the stems are shortened to reduce 
the number of buds (409c). 

c Topping is the removal of the flower stalk, as in to- 
bacco, to prevent exhaustion of the plant by the formation 

of seed. 

d Detasseling is the removal of the staminate flowers, 

(" tassels ") of undesirable plants of Indian corn, to prevent 
pollination from them (151). 



Pruning. 235 

e — Suckering is the removal of shoots that start about 
the base of the stem, or in the axils of the leaves, as in In- 
dian corn or tobacco. Its object is to prevent exhaustion 
of the plant by the production of needless shoots. 

f — Disbudding is the removal of dormant buds, to prevent 
the development of undesirable shoots. 

g — Ringing is the removal of a narrow belt of bark about 
a branch, to obstruct the current of assimilated food (138). 

h — Thinning fruit is the removal of a part of the fruits 
upon a plant, to permit the remaining ones to attain larger 
size, and to prevent exhaustion of the plant by excessive 
seed production. 

i — Deflowering or defruiting is the removal of flower-buds 
or fruits to prevent exhaustion of the plant (140). 

j — Root pruning is the shortening of the roots of plants 
in the soil, to check growth, or to stimulate the formation 
of branch roots nearer the trunk (105). 

417. The Season for Pruning. The less exhaustive 
kinds of pruning, as pinching (416a) and disbudding (416/), 
may be performed whenever the necessity for them appears. 
But in perennial plants, severe pruning, as the removal of 
branches of considerable size, is least shocking to the plant 
if performed during the dormant period. As the exposure 
of the unhealed wounds endangers damage from drjdng, 
and invites infection by injurious fungi (321), severe prun- 
ing is best performed toward the end of the dormant period, 
i. e., in early spring. Pruning should not, however, be done 
at a time when sap flows freely from wounds, as this tends 
to waste reserve food. In plants subject to this occurrence, 
as the maples and grape, pruning is probably best performed 
just before the sap-flowing period. 



2 3 6 



Principles of Plant Culture. 



418. Where and How should the Cut be Made in 

Pruning ? Since the movement of food is from the leaves 
toward the root (80), it follows that when a branch is cut off 
at some distance from the member that supports it, the 
wound cannot "heal" (73) unless there are leaves be- 
yond the wound to manufacture food, and thus make a 
growth current possible. The cut should, therefore, be made 
close enough to the supporting member so that it can be 




Fig. 153. Fig. 154. Fig. 155. 

Fig. 153. Showing the proper place to make the cut, in pruning. A wound 
made by a cut on the dotted line A-B will he promptly healed. One made on the 
line C-D or E-F will not. In Fig. 154, the lower branch was cut off too far from the 
trunk. 

Fig. 154. Showing how to make the cut in pruning large branches. The upper 
cut, all made from above, permits the branch to split down. The left cut, first 
made partly from below, prevents splitting down. 

Fig. 155. Pruning to an outside or inside bud. Cut as in the figure, the upper- 
most bud would form a shoot that tends to vertical. Cut on the dotted line, 
the uppermost bud would form a shoot tending to horizontal. 

healed from the cambium of the latter. In woody plants, 
there is usually a more or less distinct swelling about the 
base of a branch (Fig. 153), produced by the cambium of 
the supporting member and just beyond this swelling, a 
more or less distinct line marks the point where the cam- 
bium of the branch and of the supporting member unite. 
In a health}- tree, a wound made by a branch of reasonable 



Priming. 237 

size, cut off at this line, will usually heal promptly, but if 
the cut is made much farther out, it will not. 

The cut should generally be made at right angles with 
the branch, rather than parallel to the supporting member, 
since it is important that the wound be no larger than is 
necessary. Wounds so large that they cannot heal promptly 
should be painted with the Bordeaux mixture (330) to pre- 
serve the wood. 

418. Unhealed Wounds Introduce Decay into the 
heartwood of trees. Since the cells of the heartwood con- 
tain no protoplasm (72), and are alwa} T s moist, they form a 
congenial field for certain destructive fungi (321), that hav- 
ing once gained entrance, sooner or later destroy the heart- 
wood of the whole trunk, thus greatly weakening it, and 
preparing the way for the final destruction of the tree. 

419. Objects of Pruning. If intelligently performed, 
pruning has one of four objects in view, viz.: 

a — To change the form of the plant, as to outline, or den- 
sit}' {formative pruning (4 19 A)). 

b — To stimulate development in some special part, as to 
promote the growth of wood, or the formation of flower-buds 
{stimulative pruning (420B)). 

c — To prevent some impending evil to the plant as to arrest 
or exclude disease {'protective pruning (429)). 

d — To hasten maturity {matur at ive pruning (430)). 

A — Formative Pruning 

This aims to regulate the form of the plant with reference 
to outline or density, or to strength of stem. Pruning for out- 
line, includes pruning for (a) symmetry or j/icturesqueness; (b) 
for stockiness or slenderness. 



2 3 8 



Principles of Plant Culture. 



420. Pruning for Symmetry aims to develop in the 
plant a head that is symmetric with reference to its trunk. 
The general principle involved is the suppression of growth 
in all parts that tend to grow beyond the lines of symmetry. 




Fig. 156. Pruning for symmetry. The branches growing beyond the ideal 
outline, indicated by the dotted line, should be cut off at the points indicated. 

(Fig. 156). This is best accomplished by pinching (416a) 
during the growth period, thus economizing the plant's en- 
ergy; but when the pinching has been neglected, the shoots 
that grow out of symmetry ma}^ be cut back during the dor- 
mant period. 



Pruning. 



2 2>9 



In pruning for symmetry, the plant should generally be 
encouraged to develop the form that is natural to the par- 
ticular species or variety; e. g\, the American elm* tree, 
which naturally develops an open, somewhat spreading head 
that tends to be broadest toward the top, should not be 
pruned to the same form as the sugar maple f that develops 
a more roundish and compact head. Evergreens are some- 
times pruned to ideal forms, as in topiary work, a practice 
that is generally condemned by good taste. 

421. Pruning for Picturesqueness is seldom em- 
ployed. It requires a thorough knowledge of pruning and 
of plant growth, combined with the conceptions of the artist. 

422. Pruning for Stockiness aims to develop a low 
head with abundant branching, and a strong trunk. It is 

best accomplished by 
pinching (416a) the up- 
permost growing points 
during the growth per- 
iod, and encouraging 
low branching on the 
stem. If a spreading 
form is desired, the 
lower branches should 
be pruned to outside 
buds (Fig. 155). 

Pruning for stocki- 
ness is habitually prac- 
ticed in the raspberry 
(Figs. 157 and 158) and 
blackberry, in hedges and in many ornamental plants. It 
tends to the production of flower-buds, by checking growth 
of wood (137). 




Fig. 157 
pruning. 



Raspberry cane rendered stocky by 



* Ulmus Americana. 



f Acer saccharinum. 




Fig. 158. Raspberry 
cane not pruned. 

In orna- 



240 Principles of Plant Culture. 

423. Pruning for Slenderness is seldom necessary, as 
a slender growth may readily be produced by close planting. 
It is accomplished by persist- 
ently removing or cutting back 
the lower branches, and per- 
mitting only a few to develop 
near the terminus of the stem. 

424. Pruning for Density 

applies either to increasing or 
decreasing the densit} T of the head 
mental- and shade trees, a compact head is often desir- 
able, while in fruit trees, a head that admits abundant 
light and air (Fig. 162) is important (243). To increase 
density, encourage lateral branching by pinching all 
the more prominent, terminal growing points (Fig. 
160). In some coniferous trees, as the Norway spruce,* 
disbudding of the terminal shoots (Fig. 159) in spring 
is advisable, and in wood} T plants too tall for pinching, the 

more prominent terminal 
growing points may be cut 
back with the pole shears 
(431), which causes the head 
to grow more dense. 

In pruning to form an 

Fig. 159. Showing how to disbud shoots Open head (Fig. 162), it is 
of some coniferous trees. Picking out the ^ ag ft , t() ^ Qut 

terminal bud A, in spring, usually causes 

both the adjacent lateral buds to develop, the smaller branches at some 
distance from the trunk than to remove large branches at 
their union with the trunk. 

425. Pruning for Strength, a — of the Trunk. Trees 
and plants grown in closeh'-planted nursery rows often have 




* Abies excelsa. 



Pruning. 



24: 



trunks insufficiently developed to support the head, when 
planted by themselves. To remedy this defect, we promote 
the formation of new vascular bundles (68, 124) b} r inducing 
branching, which we accomplish by cutting back the top in 
proportion to the slenderness of the trunk (422). 

b — of the Branches. Trees expected to support heavy 
crops of fruit, or to endure high winds, should have branches 

developed with 
special reference 
to strength. In 
such cases, sev- 
eral medium to 
small branches 
are better able to 
endure the strain 
than a few large 
ones (2456), and 
the loss to the 
tree of a small 
branch, should it 

Fig. 160. Showing how density of growth is promoted 
(right hand side) by persistent pinching of the terminal OCCUT, IS leSS Sei'l- 
growing points. ous tllan tJlat Q f 

a large one. Forming the head of fruit trees of three or 
four main branches is to be discouraged for this reason. 
Several small branches from a common trunk are better, 
and these should be encouraged to leave the trunk at nearly 
right angles (Fig. 155). Forks in the trunk of fruit trees, 
dividing the wood into two nearly equal parts are objection- 
able, as one or the other part is verj T liable to split down 
under the weight of a heavy fruit crop. 

426. Main Branches Inclined to Split Down may 
sometimes be prevented from doing so, by twisting two 




242 



Principles of Plant Culture. 



smaller branches together, to form a connection between 
them (Fig. 163). The branches thus twisted often grow 
together, forming a tie of great strength. A main branch 
that has actually commenced to split down may often be 
saved by passing an iron bolt through it and the remainder 
of the trunk. A bolt thus inserted may become entirely 
inclosed by later growth. 










Fig. 161. Unpruned apple tree, with head too dense to admit light. 

B — Stimulative Pruning 

This depends upon the principle: the suppression of growth 
in one direction tends to stimulate it in others. Stimulative 
pruning may be employed either to stimulate growth of 
leaves, branches and roots, or of flower-buds. 



Pruning. 



2 43 



427. a — Pruning for' Growth may be performed (1) 
By removing & part of the branches, thus reducing the num- 
ber of growing points, and the surface exposed to evapora- 
tion. Plants that are not making satisfactory growth through, 
feeble root action, may often be invigorated by this treat- 




Fig. 162. Apple tree pruned with open head, to admit abundant light. 

ment, which is especially useful in trees recently trans- 
planted, or weakened by overbearing. 

(2) By suppressing reproduction. When growth is desired, 
it is often advisable to prevent the development of flowers. 



244 Principles of Plant Culture. 

Newly-planted strawberry-, raspberry- and blackberry plants 
usually make better growth the first season if the flower- 
buds are picked off. The removal of flowers in the potato 
plant tends to stimulate the growth of tubers, especially in 
varieties that form seed. The removal of flower-buds from 
cuttings in the propagating bed encourages the formation 
of roots. Topping (416c) tobacco and rhubarb plants causes 
the leaves to grow larger, and of onion plants stimulates 
growth of the bulbs. Detasseling corn (41 6d) encourages 
growth of the ears. Thinning fruit, (41 Qh) on plants that 
incline to overbear, causes the remaining fruits to grow 
larger. 

428. b — Pruning for Flowers or Fruit. Since check- 
ing growth tends to stimulate the formation of flower-buds 
(135), we encourage flowering in plants that incline to lux- 
uriant growth, by pruning that tends to check vigor. This 
ma} T be accomplished, 

(1) By pinching the terminal buds during the growth period, 
as is often practiced upon tard}^-bearing fruit trees, or 
upon seedling fruit trees of which it is desirable to earty 
learn the quality of the fruit. To be successful, it must be 
performed rather early in the growing season, and before the 
time for the formation of flower-buds. The blossoms do not 
usually appear until the season following the pinching. 

With plants that flower at the terminal growing points of 
the principal branches, as the spiraeas, hydrangeas, rhodo- 
dendrons etc., pinching to promote flowering is not advisable. 

(2) By cutting back the new growth. Woody plants that 
flower on wood more than one } r ear old, as the apple, pear, 
currant etc., when grown on rich or well-cultivated ground, 
or that have been too severely pruned, often tend to produce 
an excess of new wood with a very feeble development of 



Pruning: 



H$> 



flower-buds. In such cases, it is advisable to equalize the 
growth by a moderate cutting back oi all the young shoots. 
This must be done, however, with judgment. If the cutting 
back is too severe, it will stimulate more wood growth 
rather than the development of flower-buds. 

(3) By root pruning. This checks 
growth by reducing the number of 
root- tips, and thus cuts off a part of 
the water supply. It is applicable to 
the same cases as pinching, and is ac- 
complished b}^ cutting off the ex- 
tremities of the roots by inserting 
the spade in a circle about the plant, 
or in the case of trees of considerable 
size, by digging a trench sufficiently 
deep to sever the lateral roots. The 
severity of the root pruning advis- 
fig. 163. Branches of fruit able will depend upon the vigor of 

tree tied together by a graft 

formed by twisted twigs. the growth it is desired to check. 

(4) By obstructing the growth current. This has already 
been considered (138). When ringing is practiced, the width 
of the belt of bark removed should usually not be so great 
that the wound cannot heal over the same season, and it 
must be made sufficiently early to give time for the healing. 
In the grape vine, in which ringing is often practiced to in- 
crease the size and earliness of the fruit, the width of the 
belt removed is not important, since the canes that have 
borne fruit are generally removed in the annual pruning. 
But in fruit trees, the belt of bark removed should not 
much exceed one-eighth inch in width. Simply cutting 
through the bark with the pruning saw often accomplishes 
the end. 




246 Principles of Plant Culture. 

C — Protective Pruning 

429. Dead or Dying Members of a plant Should Be 
Promptly Removed, since the} 1 - more or less endanger its 
well-being. Dead branches of an} T considerable size invite 
decay into the stem which often results disastrously (418). 
Branches that are dying from infection b} r a fungous para- 
site, as with the apple or pear blight, or the black knot of 
the plum (323), are especially dangerous and should alwa} T s 
be removed as soon as discovered. Branches that tend to 
interfere with the growth of others ahead}' formed should 
be checked by pinching, and those that interfere 03' too 
close contact should be cut back in proportion to the inter- 
ference. 

D — Maturative Pruning 

430. This is seldom practiced. In nursery trees that 
tend to grow too late, and thus to endanger winter killing, 
the leaves are sometimes removed two or three weeks before 
the time when hard frosts are expected, to encourage ripen- 
ing of the wood. 

The later tobacco plants in a plantation are usually top- 
ped at the time the main crop is pushing the flower stalk, 
which causes their leaves to mature in season to be harvested 
with the rest of the crop. 

431. The Principal Pruning Implements are the fol- 
lowing: 

The pruning knife (Fig. 164) is useful for removing small, 
woody shoots. The blade should be of good steel, and the 
point should curve forward a little, to prevent the edge from 
slipping off the branch. The handle should be large to 
avoid blistering the hand; the base of the blade should be 
thick to furnish a support for the thumb, and the rivet 



Pruning . 



247 



should be strong enough to sustain considerable pressure 
upon the handle. 

In using the pruning knife, the shoot to be eut on" should 
general]}- be pressed with one hand toward the member ihat 
supports it and the blade should be inserted at the proxi- 
mal side. Care is necessary to prevent the blade from cut- 
ting tOO far. 

The pruning saw (Fig. 165) is useful for cutting off large 
limbs. Two toothed edges arc preferable to one, as the 
second edge tends to prevent " pinching." Tt is well to have 
the teeth on one edge point backward as this enables the 
saw to cut either when pushed or pulled. Sometimes the 
blade is curved like a sabre, with the teeth on the concave 
edge pointing backward. The blade should taper nearly 

to a point, to enable it to enter between 

crowded branches. 




Fio. 104. Fig. 165. 
Fijj. 164. Pruning knife. 
I ig. 166. Pruning shears. 



Fig. 167. 



I p.. 166. 

FJg. 166. Pruning saw. 
Fig. 167. Bedge bears, (much reduced). 

The pruning shear* (Pig. 166) may be used Cor the same 
purpose as the pruning knife, but as it cuts less smoothly, 



2 4 8 



Principles of Plant Culture. 




and less closely to the supporting member, it is not so de- 
sirable for general pruning as the pruning knife. It is. how- 
ever, excellent for cutting cions (386), and making cuttings 
(358). The form shown in the figure is perhaps 
the best one extant. 

The hedge shears (Fig. 167) is especially useful 
for pruning hedges. 

The lever shears 
(Fig. 168) is useful 
for cutting off 
sprouts about the 
base of trees. 

The pole shears 
(Fig. 169) is useful 
for cutting back 
the shoots of trees, 
and for removing 
sap sprouts (224) 
from the branches 
of tall fruit trees, 
though for this pur- w . 1fi8 Fl T Gl6 \ , h *^™" 

& r Fig. 168. Lever shears, (much reduced). 

pOSe, it has the fault Fig. 169. Pole shears. The wire connects with a 

. , ^ . lever not shown in the figure. 

Of the pruning Fjg 1?0 R asp berry hook. The handle should be 
Shears in not CUt- about three feet long. 

ting sufficiently close to the branch. It should not be used 
for shoots much exceeding one-half inch in diameter. 

The raspberry hook (Fig. 170) is used for cutting off the 
dead fruiting canes of the raspberry and blackberry. The 
cutting part is made of a rod of good steel, five-sixteenths 
inch in diameter, flattened and curved as shown, with a 
moderately thin edge on the concave side of the curve. 




CHAPTER V 

PLANT BREEDING 

43*2. Plants Have Improved Under Culture. From 
our point of view, our cultivated varieties of plants are su- 
perior to their wild prototypes. The strawberries of our 
gardens are larger, more productive and firmer than those 
of the fields; the cultivated lettuces are more vigorous, more 
tender and milder in flavor than wild lettuces; and the cul- 
tivated cabbages and cauliflower are greatly superior, in the 
food products the}* furnish, to their progenitor. The super- 
ior qualities of cultivated plants, as compared with their 
wild parents, is conspicuous whenever the wild form is known. 

433. Whence this Improvement? It probably re- 
sults from two causes. (1) In culture, the hindrances to 
development are largely removed. Cultivated plants are 
less crowded by too-near neighbors than wild plants, while 
food and moisture are often directly supplied to them. 
The}* are, therefore, able to reach higher stages of develop- 
ment than is possible in nature, where plants are constantly 
restricted by environment. 

(2) The principle of selection (19) has doubtless been 
more or less operative since the beginnings of culture. All 
of our cultivated plants must have existed originally in the 
wild state. The most satisfactory plants of any desirable 
species have been most carefully guarded, and when the art 
of propagation became known, these plants were most multi- 
plied. In each successive generation, the most desirable 

16 



250 Principles of Plant Culture. 

individual plants of each species were protected and multi- 
plied, or at least were permitted to perpetuate themselves. 
Since the offspring tends to resemble the parent (18), the 
persistent propagation from the best has resulted in more- or 
less- marked improvement. These facts furnish hints for 
the further improvement of plants. 

434. The Variability of Plants Renders their Im= 
provement Possible. In a species of which the individual 
plants are all practically alike, as in many wild plants, we 
can do little in the way of plant breeding, except to give 
treatment that promotes variability (438). In a species in 
which the individuals manifest different qualities, however, 
we may hope to secure improvement by using the most de- 
sirable plants as parents from which to secure still further 
variability. 

435. Variations are Not Always Permanent. If we 
find a chance seedling of the wild blackberry, for example, 
that has remarkably fine fruit, the plants grown from seeds 
of this fruit are not always equal in quality to the parent. 
The tendency, in such cases, is for the seedling plants to 
revert or go back to the ordinary type of the species, and 
the more marked the variation, the stronger is the tendency 
to reversion. 

436. How to Fix Desirable Variations. A fixed va- 
riation, i. e., one of which the progenj^ resembles the parent 
in all important characters, becomes a variety (21), as this 
word is used with reference to cultivated plants. There are 
two possible ways of fixing a desirable variation: 

(1) By propagating the plant by division (345). This en- 
ables us to maintain a given variation through many gener- 
ations with comparatively little deviation from the form 



Plant Breeding. 251 

with which we started (341). Our varieties of fruits, pota- 
toes, geraniums and many flowering plants, and of many of 
our finest ornamental trees and shrubs are fixed in this wa}\ 
It is well known that varieties propagated in this way rarely 
"come true" from seed, i. e., their seed does not usually 
produce plants of the same variety as the parent. But it is 
not practicable to propagate all plants by division. With 
plants more convenient^' propagated from seed, as the 
cereals, Indian corn and most garden vegetables, we may 
fix varieties to a certain extent, 

(2) By persistent selection toward an ideal type. For ex- 
ample, if we discover a single pea plant, in a row of peas, 
that produces earlier pods than any other plant, and we 
desire to fix this variation, we would save all the peas from 
this plant and sow them the next spring. Most of the plants 
from this seed will probably be later than the parent, but 
two or three of them may very likely equal it in earliness. 
We would save the seeds from the ver} T earliest plant again, 
and continue this S3'stem of selection through several sea- 
sons. It would be well to note the incidental characters of 
the earliest plants, i. e., whether the pods were borne singly 
or in pairs, and if they were straight or crooked, and whether 
the plants were tall or dwarf. Having decided on the char- 
acters that seem to accompany the extreme earliness, we 
should save seeds from no plants that do not show all these 
characters. After following this kind of selection eight or 
ten years, we may be able to introduce a new variet}' of pea. 

It is impossible to so fix variations in plants grown from 
seed that they will continue to come true without a certain 
amount of selection, hence varieties propagated by seed 
continually tend to "run out," i. e., to lose their distinctive 
characters. Seed growers find it necessarj- to use the utmost 



252 Principles of Plant Culture. 

care in maintaining their varieties, and the more marked a 
variety propagated by seed, the more difficult it is to main- 
tain. 

437. Seed Selection is of Great Importance. From 
what has been said, it is clear that the cultivator cannot 
afford to be indifferent as to the quality of the seed he sows. 
It is not enough that the seed is fresh and plump; it should 
be of carefull} T -bred varieties. In the cabbage and cauli- 
flower, success or failure in the crop will depend very largely 
upon the quality of seed sown, and the same is true to a 
greater or less extent in all crops grown from seed. 

438. We Can Induce Variation in some cases, by 
special treatment of the parent plants, or by the use of a 
particular selection of seed. 

a — By culture. It is generally conceded that culture 
tends to promote variations that would not have appeared 
in the wild state, in consequence of the changed growth con- 
ditions. In improving wild plants, therefore, we have a 
better chance of securing variation by gathering seeds from 
plants under high cultivation than from those that have not 
been submitted to culture. 

b — By growing seedlings. In plants habituall} 7 propa- 
gated by division (345), as the apple, potato, dahlia etc., we 
secure variation by growing } T oung plants from seed. The 
parent plant, not having been fixed by long selection, as is 
the case with varieties grown from seed, is in a state of va- 
riation, and hence its progeny is by no means certain to 
closely resemble it. On the contrary, it usually shows great 
variation. From these variable seedlings, desirable indi- 
viduals ma} T be selected for fixing. Since most of our vari- 
eties that are propagated by division are highly developed, 



Plant Breeding. 253 

as compared with their wild parents, their seedlings are 
usually, though not necessarily, inferior to themselves. 

c — By crossing varieties or species. We have here the 
most important key to plant improvement. B}' procuring 
fecundation of the germ cell of the ovule of a plant of one 
variety with pollen from a plant of a different variety or 
species (150) through cross-pollination (152), we obtain a 
variable progeny of which the individual plants ma} T be ex- 
pected to resemble both parents in different degrees. For 
example, if we secure fecundation of a number of ovules of 
the Worden grape with pollen from the Delaware grape, and 
carefully save and plant the seeds from the fruits thus se- 
cured, we may expect that some of the seedlings will about 
equalty resemble both parents, that others will chiefly re- 
semble the Worden, but will show a few characteristics of 
the Delaware, while others will chiefly resemble the Dela- 
ware, but will possess a few characteristics of the Worden. 
It would not be surprising if we secure a vine having the 
vigor, productiveness and large fruit of the Worden, with 
the color and delicious flavor of the Delaware. This we may 
almost certainly accomplish if we continue our trials a suf- 
ficient time. In other words, we may often combine the good 
qualities of two varieties into a single variety by securing a num- 
ber of cross fecundations between the two, and rearing plants 
from the seeds thus formed. 

439. The Selection of Subjects for Crossing. If the 

object of crossing is simply to secure variation, as is some- 
times the case with wild fruits, the parents should differ 
from each other as widely as possible, provided only that 
the}' are capable of crossing freely. Crosses between allied 
species (lrybrids 23). when this is possible, will be more 



254 Principles of Plant Culture. 

likely to accomplish the object sought than between plants 
of the same species. 

If the object is the improvement of present varieties, the 
parents should be chosen with reference to the qualities de- 
sired in the new variety. For example, if it is desired to pro- 
duce a hardy, late-keeping apple, of first quality, any hardy 
variety that keeps well, whatever its quality, may be crossed 
with any other apple of first quality, whether it keeps poorly 
or well, though of two apples of first quality, the better 
keeper should be chosen. 

The plant breeder should first have a very definite idea of 
the qualities he desires to secure in his proposed variety, 
and should then study with much care the qualities of the 
varieties that he proposes to use as parents. The two vari- 
eties that contain the largest number of the desired qualities 
should be crossed. 

440. Cross Fecundation is accomplished through 
cross pollination of the flowers (152); i. e., by placing pollen 
from the* anthers of a flower of one of the varieties we desire 
to cross, upon the stigma of the other variety. 

441. Preparation of the Flower. To prevent self 
pollination (152), we are careful, in the case of perfect- 
flowered plants (154), to remove the anthers (144) before the 
pollen is mature. Prior to maturity, the anthers are gener- 
ally pale in color and nearly smooth on the surface, with no 
visible pollen, but a little later, the pollen in most plants is 
visible as a bright-yellow dust adhering to the anthers. 
The anthers may be picked off carefully with the forceps, or 
the filaments that support them may be clipped off with the 
points of the scissors. The anthers must generally be re- 
moved before the petals open. The latter may be gently 



Plant Breeding. 



255 




FRt. 171. Case of instruments and sacks 

To Prevent Un= for crossin g plants. 



opened with the forceps or needle. The removal of the 
anthers is termed emasculation (e-mas-cu-la'-tion). 

In the flowers of certain 
plants, as the pea, wheat and 
grape, pollination takes 
place before the blossom 
opens. In these plants, it is 
necessaiy to emasculate the 
flowers veiy earl}'. 

desired Pollination, the blossom should be inclosed by 
tying over it a sack of thin cloth or paper at the time of re- 
moving the anthers. The sack will of course have to be 
removed for pollination, after which it should be promptly 

replaced. 

Pollination should be 

performed twenty-four to 
fort} T -eight hours after 
emasculation (441), the 
period depending upon the 
plant, and the stage of 
development of the flow- 
ers at the time of the 
latter operation. Apply- 
ing the pollen on two con- 
secutive days tends to in- 
sure success. 

The pollen is applied by 

Emasculated flower inclosed in sack. placing an anther {U4) 

containing mature pollen in direct contact with the stigma 
(145), or by removing some of the pollen upon the back of 
the point of a penknife, or b} T means of a camel's-hair 




256 Principles of Plant Culture. 

brush, and carefully applying it to the stigma. A pin, of 
which the head has been flattened b} T hammering, inserted 
in the end of a stick, forms a convenient tool for this work. 
The best time for pollination, in the open air, is often in 
the early morning, since the atmosphere is then usually still, 
and contains little pollen from other flowers, which, if freely 
present in the air, is liable to vitiate the results of our pol- 
lination. 

443. The After Care of Crosses. After the last pol- 
lination, the blossom should be again inclosed until fecun- 
dation is effected, which is indicated b}' a rapid enlargement 
of the ovaiy. The paper sack ma} T then be replaced hy one 
of mosquito netting. This should be securely, but not too 
tightly, tied about the stem of the pollinated flower, to pro- 
tect the inclosed fruit or seed-vessel from injury during 
growth and maturity, as well as to render it conspicuous. 
A label should be placed within the sack, or tied on with it, 
giving the name of the variet}' whence the pollen was se- 
cured. It is desirable, also, to keep a notebook, in which 
all the operations and observations relative to the crossing 
are recorded. 

444. The Selection of Crossed Seedlings is a most 
important operation in producing new varieties by crossing. 
If none of the seedlings of the first generation exhibit the 
desired qualities, the attempt need not be regarded as a 
failure, since those of a succeeding generation may exhibit 
them. The plants nearest the ideal should be selected, and 
all the seeds from these preserved for planting. When the 
ideal plant is found, it may be readily fixed hy means of 
cuttings or grafts in plants generall}' propagated in this 
way. But in those propagated by seed, several generations 



Plant Breeding. 257 

of culture and selection may be necessary before the progeny 
will uniformly resemble the parent. 

The variations in the seedlings from two crossed varieties, 
and the kind of selection needed to fix the desired variation, 
are illustrated by the following diagram (Fig. 173). Let a 

A I , 



Fig. 173. Diagram illustrating the selection of seedlings from a cross. 

represent the seeds from two crossed flowers A and B. The 
plants from these seeds will probably be quite variable, as is 
indicated by the divergent lines. Let us suppose the varia- 
tion marked i to be nearest the ideal form. The plants 
grown from i will be again quite variable in the second gen- 
eration b, but probabty less so than in the first generation. 
No plants of the second generation may be nearer the ideal 
type than those of the first generation, but we select the 
plant nearest to our ideal, and plant the seeds from this. 
Each succeeding generation ma} T be expected to produce 
less of variability than the one before it. Bye and b}'e, we 
may hope to secure a form that approaches our ideal and 
that comes tolerably true from seed. 

445. Planting with Reference to Chance Crossings. 

Man}' valuable varieties of fruits have unquestionably arisen 
from accidental crosses between plants of different varieties 
that chanced to be growing in proximity. Profiting b} T this 
hint, varieties are sometimes planted near together to favor 
the accidental crossing of the flowers, a practice to be en- 
couraged. 



258 Principles of Plant Culture. 

446. Those Who Improve Plants are True Benefac= 
tors. He who produces fruits or flowers for others works ,a 
transient good. But he who produces a variety of fruit or 
flower that is superior to any now known confers upon his 
race a permanent good. Until the introduction of the Wil- 
son strawberr}-, the markets of our country were not sup- 
plied with this delicious and wholesome fruit, because no 
known variety was sufficiently productive to be generally 
profitable, or sufficiently firm to endure long carriage. What 
a blessing was conferred upon us by a Mr. John Wilson, of 
Albany, N. Y., of whom little appears to be known except 
his name ! There are wild fruits in our copses to-day 
scarcely less promising than was the strawberry of our fields 
a century ago, and in many of our fruits now under culture, 
the development of superior varieties would greatly enhance 
their value. " The harvest truly is great, but the laborers 
are few." 



The following books are recommended for reading in con- 
nection with Chapter IV: The Nursery Book, Bailey; Green- 
house Construction, Taft; Barry's Fruit Garden, Barry; The 
Art of Grafting, Baltet; The Pruning Book, Bailey; How to 
Make the Garden Pay, Greiner. 



The following are recommended in connection w 7 ith Chap- 
ter V: Plant Beeeding, Bailey; Variations of Animals and 
Plants Under Domestication, Darwin; Propagation and 
Improvement of Cultivated Plants, Burbridge; Origin of 
Cultivated Plants, De Candolle. 



APPENDIX. 



A SYLLABUS OF LABORATORY WORK 

The laboratory exercises here outlined have been used by 
the author in his instructional work. The} T are presented 
because several instructors have expressed a desire for such 
a syllabus. 

While these exercises have proved both interesting and 
profitable to students, the author does not consider the sys- 
tem fully developed, and he will be grateful for suggestions 
that will tend to make it more useful. 

It has not been found practicable to make the lecture 
room and laboratory work fully correspond as to time, but 
the effort has been made to do this so far as possible. 

When the exercises are carried out during the winter 
months, a considerable foresight is essential to have the 
needed materials in condition for use at the proper time. 
. It is understood that each student performs the exercises 
outlined, so far as possible, and the apparatus needed is 
provided. The student should be required to write a de- 
scription of the work performed, stating results in every 
case, supplementing his notes by drawings in special cases. 

A greenhouse is almost indispensable to the kind of in- 
struction here described, and if the instruction is given in 
winter, a "garden house," i. e., a glass house inclosing an 
unobstructed area of garden soil is scarcely less important. 

A Syllabus of Laboratory Instruction 

The numbers in parethesis refer to the paragraphs in the book. 

Cell structure (12). The students examine the pulp of a 
mealy apple and of a potato and cross sections of a young 



160 Principles of Plant Culture. 

bean plant, with simple lenses of rather high magnifjing 
power. If a compound microscope is available, many 
mounted objects illustrating the cell structure of plants are 
also shown. 

Absorption of water by seeds (26). Each student is pro- 
vided with a graduated glass cylinder of at least 50 cubic 
centimetres capacity, (one to each pair of students will an- 
swer), and two bottles of at least 100 c. c. capacity, with 
corks. Each bottle should have a strip of white paper 
pasted vertically upon it to receive the name of the student 
and other data. 

Each student measures the volume of 50 fresh seeds of 
the bean, pea, or Indian corn, by dropping them into the 
graduated cylinder that has first received 25 c. c. of water. 
The height to which the water rises after receiving the seeds 
is then quickly and accurately noted, when the volume of 
the seeds is determined by substracting 25 c. c. from this 
reading. The student then pours the seeds, with the water, 
into one of his bottles, corks the latter and writes his name, 
with the date, on the paper pasted on its side. He then re- 
peats the process with seeds of the honey locust, 3 T ellow 
wood or some other seed that does not readily absorb cool 
water, and after recording the data in his notebook, places 
the bottles in a warm place until the following day, when 
he again measures the volume of the two kinds of seed. 
The seeds placed in the first bottle will usually be found to 
have nearly or quite doubled in size while those in the sec- 
ond bottle have scarcely swollen at all. 

Next, show the class a sample of the second lot of seeds 
that have fully swollen from soaking in hot water. Impress 
upon their minds the fact that while most seeds readily absorb 
moisture at ordinary temperatures, a few kinds do not, and 
seeds of the latter class need to be soaked cautiousl}' before 
planting, in hot water, until they swell (27d). 

The rate at ivhich seeds absorb water depends 

a — Upon the water content of the medium (27).* Determine 
the volume of 3 samples of navy beans. Place one sample 
in water, a second in very damp earth and the third in 

* In the three exercises under this head, the volume of the seeds needs to be 
determined the first time without wetting them, hence very fine clean sand is used 
instead of water in the graduated cylinders. The sand should be carefully shaken 
down between the seeds in every case. While the sand is somewhat less accurate 
than water, the principles stated may be readily demonstrated by this means. 



Appendix. 261 

slightly damp earth. The next day, determine the increase 
in volume of the three lots. 

(b) — Upon the points of contact. Determine the volume of 
two samples of nav} 7 beans, placing one sample in moist soil 
without compacting, and the second in the same kind of soil 
well compacted about the seeds. Determine the volume of 
the two samples again the next day. 

(c) — Upon temperature. Repeat the above with two sam- 
ples of navy beans, placing one lot in a temperature of 80° 
to 90° degrees F., and the other in one of 40° to 50° F. 

Germination (28). An exercise in testing seeds with the 
apparatus shown in Fig. 5. 

Moisture essential to germination (29). Soak one lot of navy 
beans in water until the} 7 are fully swollen, and another lot 
until they are about half swollen. Wipe the beans as dry 
as possible, put each lot into a bottle, cork the bottles, and 
set them in a warm room. The fully-swollen beans will 
generally germinate promptly, while the others will not. 

Oxygen essential to germination (31). Perform the saucer 
experiment as described. 

Also place seeds of rice in two bottles, and add to each 
water that has been boiled 20 minutes; cover the water in 
one bottle with a little olive- or cotton-seed oil. It is im- 
portant to soak the seeds a short time in boiled water 
before putting them in the bottles to remove the air in con- 
tact with their seed-cases. 

Germination hastened by soaking seeds (36). Soak seeds of 
Indian corn two or three hours in warm water, and let each 
student place in a seed tester a sample of the soaked seeds, 
with one of other seeds of the same kind that have not been 
soaked. 

Germination hastened by mutilating the seed-case (37). This 
may be illustrated with seeds of the navy bean, in the seed 
tester. 

The plantlet (41). Place seeds of radish, onion etc., loosely 
on the surface of a saucer filled with fine moist loam; keep 
the surface moist and note the repeated attempts of the 
hypocotyl to enter the soil. 

Seeds of the pumpkin family should be planted flatwise (43). 
Plant seeds of the pumpkin or squash, in the three positions 
indicated, in large greenhouse saucers. Cover each saucer 
with a pane of glass and place all in a warm room until the 



262 Principles of Plant Culture. 

plantlets appear, after which note the number of each lot of 
seeds of which the cotyledons appear above the surface. 

Development of plantlets (45-47). Devote several exercises 
to a thorough study of the development of plantlets of the 
bean, pea, wheat, Indian corn, pumpkin etc. Seeds of the 
different sorts should be planted, to furnish the plantlets, on 
several successive days, beginning at least 10 days in ad- 
vance. 

Not all seeds may be deeply planted (48). Plant seeds of 
the bean, pea, Indian corn and wheat in 6-inch flower pots, 
at 3 different depths, viz., ^ inch, 3 inches and 6 inches from 
the bottom; place the pots in a warm place for 3 weeks, 
after which carefulty remove the soil, noting the germina- 
tion of the seeds in the different layers. 

Vigor of plantlet proportionate to size of seed (49). Plant 
large and small specimens of navy beans, by themselves, in 
greenhouse saucers, and permit them to germinate. The 
smaller seeds usually germinate earlier than the larger, but 
they produce more slender plantlets which soon fall behind 
the others in development. 

Plantlet visible in the seed (54). Boil samples of various 
kinds of seeds until they are fully swollen, after which re- 
quire the students to dissect them and to seek out the plant- 
lets. Lenses, needles and forceps are very useful in this 
work. 

The cotyledons a storehouse for food (60). Remove the 
cotyledons of some bean plantlets growing in a flower pot or 
saucer, leaving those of other plantlets intact. After a week, 
note the result in the checked growth of the mutilated plants. 

Vascular bundles (68). Study these as shown in the stalk 
of Indian corn, in the leaf stems of various plants and in 
the leaf scars on the stems of plants. 

Cambium layer (69). Locate this in sections of various 
dicotyledonous stems, including the potato tuber; also note 
the absence of the cambium layer in monocot} 7 ledonous 
stems. 

Root-hairs (101). Study these as illustrated when seeds 
germinate in the seed tester. Germinated radish-seeds, left 
in the seed tester two or three days, usualty develop root- 
hairs in great abundance. Also search out the root-hairs 
in potted plants. Emphasize the difference between root- 
hairs and root branches. 



Appendix. 26 



j 



Effects of transplanting on root branching (105). Study 
young plants of lettuce, tomato, cabbage etc., that have 
been pricked off, and compare their roots with those of 
others that have not been pricked off. 

Relation of roots to food supply (112). Plant seeds of the 
radish in saucers containing clean sand and potted soil re- 
spectively, and when the seedlings have attained some size, 
wash out and examine the roots in the two soils. 

Root tubercles (113). Study the roots of young clover 
plants of various ages, and note how early in the develop- 
ment of the plant the tubercles are discernable. 

Underground stems (115). Study the development of the 
potato plant from growing specimens, noting the points at 
which the tuber-bearing stems originate, and the marked 
difference between these and the roots. 

Nodes and internodes (116). Observe the nodes in the 
stems of many plants, noting the relation of the diameter 
of the young stem to the length of the internodes; also, note 
the undeveloped internodes^ near the terminus of the stem. 

Buds (128). Study specimens of leaf-buds from many 
plants, noting their structure, position etc. 

Flower-buds (133). Stud} 7 the form and location of the 
flower-buds in many plants, particularly in fruit trees. 

Parts of the flower (141). Stud} 7 the parts of the flower, 
explaining the function of each part. 

Perfect and imperfect flowers (154). Study these as pro- 
duced by several different plants, particularly of the straw- 
berry. 

Degree of maturity necessary to germination (163). Test 
seeds of Indian corn, pea, tomato etc., that were gathered 
at varying stages of maturity. 

Seed vitality limited by age (165). Test seeds of lettuce, 
parsnip, onion etc., 1 year, 2 years and 5 years old respectively. 

Stratification of seeds (170). Perform the process, as de- 
scribed, in boxes or large flower pots. 

Sun-scald (186). Require each student to make a lath 
tree protector (Fig. 58). 

Winter protection of plants (202). Protect half-hardy 
shrubs by wrapping them with straw or covering them with 
earth. 

Foretelling frost (207). Devote an exercise to the use of 
the psychrometer and the computation of the dew point. 



264 Principles of Plant Culture. 

Plant protectors (279). Require each student to make at 
least one plant protector, as shown in Fig. 56, patterns for 
which are to be furnished. 

Kerosene emulsion (294). Let each student make a given 
quantity of the kerosene emulsion after one of the formulas 
given. 

Spraying pumps (304). Grive at least one exercise to the 
construction and use of spra}ing pumps and nozzles. 

Prevention of grain smuts (325). Require the students to 
treat a quantity of oats to hot water as described. 

Bordeaux mixture (329). Require each student to make 
a stated quantity of the Bordeaux mixture after the for- 
mula given. 

Propagation by seeds (344). Instruct the students in the 
use of the hand seed-drill and broadcast sower. Let them 
ascertain now much clover seed the broadcast machine is 
sowing per acre, b}^ laying on the ground or floor several 
sheets of paper, exactly one foot square, painted with 
glycerine to catch the falling seeds. Having learned the 
average number of seeds deposited per square foot with a 
given rate of motion of the machine, let the students com- 
pute the number of seeds sown per acre, and reduce this to 
ounces. The number of clover seeds in an ounce may be 
ascertained by dividing an ounce of the seed among the 
students for counting. 

Propagation by layers (349). Instruct the students in lay- 
ering canes of the grape, and in mound-layering the stems 
of the gooseberry. 

The bulb (352). Dissect bulbs of the onion, tulip, lily etc., 
ascertaining their structure and finding the embryo 
flowers. 

The cold-frame (364). Require the students to make a 
drawing and write a description of a cold-frame, from a 
model furnished them. 

The hotbed (365). Let the students assist in making a 
hotbed after the plan described. Also let them note the 
temperature of the soil within the frame on several succes- 
sive days after the bed is finished, and give them instruction 
in ventilating the hotbed. 

The propagating bed (368). Require the students to make 
a propagating bed in the greenhouse, after the plan described. 

Stem cuttings (373-375). Let the students make cuttings 



Appendix. 265 

from the stems of the grape, currant, etc., and plant them, 
both in the propagating bed and in the garden. 

Root-cuttings (376). Give a lesson in making root cuttings 
of the blackberry, in packing the same for winter storage, 
and in planting them in the propagating bed, and in the 
garden. 

Green cuttings (380-381). Give a lesson in making and 
planting cuttings of coleus, geranium, rose etc., followed by 
instructions on the care of green cuttings in the propagat- 
ing bed. 

Leaf cuttings (382). Give a lesson in making and plant- 
ing leaf cuttings of the begonia. 

Grafting wax etc., (3S7-389). Give a lesson in making 
grafting wax, grafting cord and grafting paper, as described. 

Whip-grafting (390-391). Give several lessons in whip 
grafting including grafting both of the stem and of the root. 

Cleft grafting (392). Give one or two lessons in cleft 
grafting. 

Side grafting (393). Give a lesson in side grafting, as 
described. 

Budding (394). Give one or more lessons in budding, as 
described. The bark on the stocks may be made to peel by 
boiling, and trimmed bud sticks may be preserved, for 
winter use, in dilute alcohol. 

Approach grafting (399). Give one exercise in approach 
grafting, as described. 

racking plants for transportation (405). Devote one exer- 
cise to packing strawberry, cabbage or some other herbace- 
ous plants, as described. 

Heellng-ln, Replanting (408-410). Give one or more les- 
sons in heeling-in and planting trees, as described; also at 
least one lesson in planting root grafts, cuttings and herb- 
aceous plants as shown in Figs. 142-143; and a lesson in 
planting strawberr} T plants, as shown in Figs. 144-145. 

Potting and shifting (412). Give two or more lessons in 
potting and shifting, as shown in Figs. 146-149. 

Pruning (427 etc.). Give one or more lessons in pruning 
by the methods described. 

Cross pollination (441). Give one or more lessons in cross 
pollination, as described. 

17 



INDEX 



The numbers refer to pages. 



Accumulation of reserve food, how to 
promote, 88. 

Acid phosphate, 145. 

Active state of protoplasm, 14. 

Adventitious buds, 83. 

Aeration of soil promoted by drainage, 
66. 

Air-dry defined, 14. 

Air, roots require, 63, 64. 

Ammoniacal solution of copper car- 
bonate, 170. 

Ammonium sulfate, 144. 

Animal parasites, 148. 

Animals, domestic, defined, 11. 

Annular budding, 213. 

Anther, 91. 

Apparatus for applying insecticides, 158* 

Appendix, 259. 

Apple, blight of, 166, 246. 

Approach grafting, 181, 204, 217. 

Army worm, 157. 

Arsenic compounds, 151; are deadly 
poisons, 152. 

Arsenic, white, 152. 

Arsenious acid, 152. 

Arsenite of copper, 151; of lime, 152. 

Art and science defined, 9; how best 
learned, 10. 

Assimilated food, current of, 59. 
Assimilation defined, 41. 
Assimilation, the function of leaves, 78. 

Baldridge transplanter, 229. 
Books recommended for collateral read- 
ing, 109, 174, 258. 
Bark bursting, 117. 
Bark, epidermis replaced by, 47. 
Bemis transplanter, 229. 
Birds, damage from, 148. 
Black-h*art, 116. 



Black knot of plum, 166, 246. 

Blanching of vegetables, 138. 

Blight of apple and pear, 166, 246. 

Bloom defined, 47. 

Board screen for shading young plants, 
135. 

Bordeaux mixture, 169; diseases pre- 
vented by, 170. 

Borers, 161. 

Branches, development of, from lateral 
leaf-buds, 83; of trees, to prevent 
splitting down in pruning, 24 1 . 

Branching stimulated by pinching, 78. 

Branching of roots, conditions affect- 
ing, 71; how stimulated, 71. 

Breeding defined, 17. 

Brittleness of plant tissues, 57. 

Broom rape of hemp and tobacco, 164. 

Brush screen for shading young plants, 
135. 

Bud, 203, 214. 

Budding, 204, 212; annular-, 213; ring-, 
213; shield-, 213; success in dependent 
on, 213; T-, 213. 

Budding knife, 216. 

Buds, 82; adventitious, 83. 

Buhach, 153. 

Bulb, 182. 

Bulbels, 183. 

Bulblets, 183. 

Bundling trees for transportation, 2-23. 

Calcium, part played by in plant. 43. 

Callus, how formed, 54. 

Calyx, 90. 

Cambium, cambium layer, 50; from dif- 
ferent plants may unite, 52. 

Carbon, proportion of in vegetable ma- 
terial, 42; sources of, in plants, 42. 

Caulicle, 31. 



Index. 



267 



Cauliflower heads to be shaded from 
sunlight, 136. 

Caustics, destroying insects by, 151. 

Cell division, 15. 

Cells, guard, 47, 48; palisade, 47; some 
properties of, 13. 

Cellular structure of living beings, 13. 

Chili-saltpeter, 144. 

Chinch-bug, 157. 

Chlorid of potash, 145. 

Chlorophyll defined, 40; forms only in 
light, 40; iron essential to formation 
of, 43; no food formed without, 41. 

Chlorophyll bodies, 40. 

Cion, 203. 

Cion grafting, 204. 

Classification defined, 17; illustrated, 18. 

Cleft grafting, 209. 

Close pollination, 96. 

Clouds tend to avert frost, 125. 

Clover, dodder of, 165. 

Codling moth, 162. 

Cold air drainage, 125. 

Cold, excessive, how affeeting the plant, 
113. 

Cold-frame, 188. 

Composite flowers, 93. 

Conditions affecting power of plants to 
endure cold, 114. 

Cooling the plant, immediate effect of, 
113. 

Copper carbonate, ammoniacal solution 
of, 170. 

Corm, 183. 

Corn, detasseling, 242. 

Corolla, 91. 

Cotyledons defined, 33. 

Covering of seeds in planting, why im- 
portant, 31. 

Cracks in fruits and vegetables due to 
excessive moisture, 130. 

Crop, affected by age of seed, 103; a 
growing, tends to conserve fertility, 
146; removal of, tends to reduce plant 
food in the soil, 141; rotation of, econ- 
omizes plant food, 146. 

Crops, trees detrimental to neighbor- 
ing, 57. 

Crossed seedlings, selection of, 256. 



Crosses, after care of, 256; and hybrids 
defined, 19: variability of, 20. 

Cross fecundation, how accomplished, 
254. 

Crossing, selection of subjects for, 253; 
variation produced by, 253. 

Crossings, planting with roference to 
chance, 257. 

Cross pollination, 96; advantage of, to 
plants, 96. 

Cucumber, screen-covered frame for 
protecting hills of, 150. 

Cucurbitse, provision in, to aid plantlet 
to emerge trom seed-case, 32. 

Cultivation tends to prevent drought, 
133. 

Culture, aim of, 11; deals with life, 12; 
defined, 10; plants have improved 
under, 249; variation produced by, 252. 

Current, evaporation, 57; of assimilated 
food, 59. 

Cuticle defined, 47. 

Cutting, essential characters of a, 186. 

Cuttings, 185. 

Cuttings, conditions favoring growth of, 
186; from active plants, 198; from dor- 
mant plants, 194; from dormant 
stems, 195; of woody plants, prefer- 
ably made in autumn, 108; parts of 
plants to be ased for, 186; planting in 
autumn, 195; storage of, 194; tool for 
planting, 228. 

Cuttings, green, 198; especial care nec- 
essary in propagating plants from, 199; 
how made from herbaceous plants, 200; 
how made from woody plants, 201; to 
be potted as soon as roots are formed, 
200. 

Cuttings, leaf, propagation by, 201. 

Cuttings, mallet, 195. 

Cuttings, root, 197. 

Cuttings, stem, 195. 

Dalmatian insect powder, 153. 

Damage from cold prevented by protect- 
ing with non-conducting material, 
119. 

Damping off, 200. 

Darkening of wood, 116. 



268 



Principles of Plant Culture. 



Deflowering defined, 235. 

Defruiting defined, 235. 

Density, pruning for, 240. 

Depth of roots in soil, 73. 

Destruction of terminal buds by cold, 
116. 

Detasseling, 234, 242. 

Devices for transplanting, 227. 

Dew point, how to compute the, 124; 
table for computing, 123. 

Dibber, 227. 

Dicotyledones defined, 34. 

Diffusion, law of, 45. 

Dioecious flowers, 97. 

Disbudding defined, 235. 

Disease defined. 13. 

Distal defined, 76. 

Dodder of cloTer and flax, 165. 

Domestic plants ana animals defined, 
11. 

Dormant state of protoplasm, 14. 

Drainage promotes soil aeration, 66; 
required by potted plants, 67. 

Dressing defined, 234. 

Drought causes toughness of plant tis- 
sue, 132; cultivation a preventive of, 
133; mulching a preventive of, 133; 
tends to hasten maturity, 132. 

Drying kills plant tissues, 134. 

Duration of germinating power, 101; of 
seed vitality, c mditions affecting, 102. 

Electric arc light, use of, in glass houses, 

137. 
Elements essential in plant food, 42 

part played by different, 42. 
Emasculation of flowers, 255. 
Embryo defined, 38. 
Endosperm defined, 38. 
Environment defined, 10; factors of, 110. 
Epidermis defined, 46; replaced by bark 

in older stems, 47. 
Evaporation current, 57. 
Evergreen trees destroyed by untimely 

warm weather in spring, 111. 
Evolution, theory of, 20. 

Factors of environment, 110. 
Families, how formed. 18, 



Farm manure, 146. 

Fecundation, 95; cross-, how accom- 
plished, 254. 

Feebleness defined, 12. 

Ferns, how grown from spores, 37. 

Fertilization, 95. 

Fertilizer requirements of crops, 146. 

Filament, 91. 

Fir tree oil, 156. 

Fibro-vascular bundles, 49. 

Fixing desirable variations, 250. 

Flax, dodder of, 165. 

Flower, 90; certain parts of, often want- 
ing, 93; parts of the, 90; parts of, vary 
in form in different species, 92. 

Flower-buds, 84; conditions affecting 
formation of, 86; destroyed by cold, 
118; how distinguished from leaf-buds, 
84; ringing often causes formation 
of, 89. 

Flowering and fruiting, root pruning to 
promote, 245. 

Flowering glumes, 94. 

Flowering, pinching to promote, 244. 

Flowers, composite, 93; especially sen- 
si' ive to cold, 118; of the grass fam- 
ily, 94; tend to exhaust the plant, 90. 

Flowers and fruit, obstructing growth 
current to promote, 245; pruning for, 
244. 

Flow of sap in spring, 58. 

Food, current of assimilated, 59; ele- 
ments of, most likely to be deficient 
in the soil, 142; materials of, how dis- 
tributed through plant, 45; reserve, 
15; storage of reserve, 60; use of re- 
serve, 61. 

Food supply, insufficient, dwarfs the 
plant, 141; relation of roots to, 75; 
unfavorable, effect of, on the plant, 
140. 

Formative pruning, 237. 

Formula for Bordeaux mixture, 169. 

Formulas for kerosene emulsion, 154, 
155; for resin washes, 155, 156. 

Freezing of plants, favored by much 
water in plant tissue, 113. 

Freezing, severe, may split open tree 
trunks, 117. 



Index. 



269 



Frost, conditions that tend to avert, 
125; how foretold, 122; plants injured 
by, how saved from serious damage, 
115; liability to, depending compara- 
tively little upon latitude, 126; local- 
ities most subject to, 125; methods of 
preventing injury by, 127. 

Frozen tissues, treatment of, 115. 

Fruit, 98; or flowers, pruning for, 244; 
thinuingof, 99, 244. 

Fruitfulness promoted by restricting 
growth current, 60. 

Fruiting, obstructing growth current to 
promote, 245; root pruning to pro- 
mote, 245. 

Fruits and vegetables, cracks in, caused 
by excessive moisture, 130; rarely 
develop without fecundation. 98; 
ripening of, 100. 

Fungi, 165; endophytic, 166; epiphytic, 
171; methods of controlling, 166. 

Fungicides, 166. 

Fungous diseases, need of consulting 
specialists in, 172. 

Gathering and storing of seeds, 100. 

Genera, how formed, 18. 

Generic, named defined, 19. 

Genus, how formed, 18. 

Germinating power, duration of, 101. 

Germination defined, 23; dependent on 
stage of maturity of seeds, 100; has- 
tened by compacting soil, 27; hastened 
by mutilating seed-case, 29; hastened 
by soaking seeds, 28; in water, 26; 
moisture essential to, 24; not hindered 
by light, 31; oxygen essential to, 25; 
promptness in, important, 27; requis- 
ites for, 26; retarded by excess of 
water, 27; seed-case in, 31; tempera- 
ture at which takes place, 25; time 
required for, 30; waimth essential to, 
24; when completed, 23. 

Germinations, earlier form more vigor- 
ous plantlets, 36. 

Girdling, killing trees by, 59. 

Glumes, 94. 

Gophers, damage from, 148. 

Gormands on fruit trees, 130. 



Graft, 203. 

Grafting, approach-, 204, 217; eion-, 204; 
cleft-, 206, 209; -cord, 206; herbaceous, 
211; how possible, 52; objects of, 203; 
-paper, 206; plants uniting by, 203; 
propagation by, 202; root-, 207; side-, 
206, 210; top-, 207; veneer-, 211; -wax, 
how made, 205; whip-, 206. 

Grafts, whole- root, 208. 

Graminete, flowers of, 94. 

Grass family, flowers of, 94. 

Grasshoppers, 157. 

Greenhouse, 190; heating devices for, 
191. 

Growing point defined, 49. 

Growth by cell division, 15; cutting 
back new, to promote flowering, 244; 
decline of, 105; defined, 15: in diame- 
ter, of stems, 51; of roots in length, 
67; pruning for, 242; relation of, to 
reproduction, 16; retarded by insuf- 
ficient moisture in soil, 132; tardy 
starting after transplanting, 233; wa- 
ter necessary to, 43. 

Growth current, obstructing, to promote 
flowering and fruiting, 245; restric- 
tion of, 60. 

Guard-cells, 47, 48. 

Hardiness defined, 13; of plants, 106. 

Healing of wounds, 53. 

Health defined, 13. 

Heat, excessive, how affecting plants, 

110. 
Hedge shears, 248. 
Heeling-in plants, 223. 
Hellebore powder, 152, 153. 
Hemp, broom rape of, 164. 
Harbaceous grafting, 211. 
Herbaceous stems defined, 51. 
Heredity, and variation, 16. 
Hermaphrodite flowers, 97. 
Hoarfrost, cause of, 121. 
Horizontal extent of roots, 73. 
Host (of parasites) defined, 20. 
Hotbed, the, 188. 

Hotbeds require care in ventilation, 66. 
Hot water for destroying insects, 156; 

treatment for grain smut, 167. 



270 



Principles of Plant Culture. 



Humidity, methods of controlling, 193. 

Hybrids and crosses denned, 19. 

Hydrocyanic gas, 156. 

Hydrogen, source of in plants, 42. 

Hypocotyl denned, 31; develops differ- 
ently in different species, 35; roots 
start from, 33; seeds in which it 
lengthens must be planted shallow, 
35. 

Ice often destroys low plants, 118. 

Immature vs. ripe seeds, 101. 

Imperfect flowers, 97. 

Implements for pruning, 246; for trans- 
planting, 227, 228, 229. 

Improvement possible through plant 
variability, 250. 

Individuals defined, 17. 

Injury by cold, methods of averting, 
119. 

Insecticides, 151; apparatus for apply- 
ing, 158; use of, 158. 

Insects, beneficial, 149; burrowing, 160, 
161; destroying by poisons or caustics, 
151; eating, 159; hand-picking, 150; 
injurious, life history of 164; leaf- 
eating, 159, 160; ravages, method of 
preventing, 149; repelling, by means 
of offensive odors, 150; root-eating, 
159, 160; sucking, 159, 163. 

Insects, trapping, 150. 

Internodes defined, 76; stem lengthens 
by elongation of, 77; ultimate length 
of, 78. 

Iron essential to formation of chloro- 
phyll, 43. 

Irrigation, 133. 

Kainit, 145. 

Kerosene applied with water, 155; as 
an insecticide, 154. 

Kerosene emulsion, formulas for, 154, 
155. 

Killing trees by girdling, 59. 

Knife, budding, 216; grafting, 208; prun- 
ing, 246. 

Knowledge, application of essential to 
success. 10. 

Lath screen for shading young plants, 
134. 



Leaf-buds, 84; comparative vigor of, 85. 
Leaf cuttings, propagation by, 201. 
Leaf development, importance of, 79. 
Leaf fall, time of, an index of wood 

maturity, 106. 
Leaf eating insects, 159, 160. 
Leaf-miners, 162. 
Leaves, 78; are usually short-lived, 81;. 

comparative size of, 80; function of, 

78; manurial value of, 81. 
Leguminous plants enrich the soil with 

nitrogen, 144. 
Lenticels, 48. 
Lever shears, 248. 
Life, culture deals with, 12. 
Life, what is it? 12 
Lifting large trees, 220. 
Lifting the plant, directions for, 219. 
Light does not hinder germination, 31. 
Light, unfavorable, how affecting the 

plant, 134. 
Living beings, cellular structure of, 13. 
Localities most subject to untimely 

frosts, 125. 
Locusts, 157. 
London purple, 152. 
Low plants often destroyed by ice, 1 18. 

Magnesium, part played by, in plant, 43. 

Mallet cuttings, 195. 

Manure increases water-holding capac- 
ity of soil, 43. 

Manurial value of leaves, 81. 

Maturative pruning, 246. 

Maturity of plants, influence of drought 
on, 132. 

Maximum defined, 24. 

Melons, screen-covered frame for pro- 
tecting hills of, 150. 

Mice, damage from, 148. 

Minimum defined, 24. 

Moisture, an enemy to stored seeds, 102, 
essential to germination, 24; excess- 
ive, causing cracks in fruits and veg- 
etables, 130; excites root growth, 62; 
excessive in air, injurious to plants, 
131; insufficient in air, causing exces- 
sive transpiration, 131; insufficient in 
soil, retards growth, 132. 



Index. 



271 



Monocotyledones defined, 35. 
Monoecious flowers, 97. 
Mound-layering, 180. 
Mulching tends to prevent drought, 133; 

transplanted stock, 232. 
Muriate of potash, 145. 

Names, scientific, why used, 19. 

Nitrates in the soil, sources of, 142. 

Nitrification, 142, 143. 

Nitrogen, 142, 144; in protoplasm, 42; 
in rain and snow, 144; sources of in 
plant, 42; stimulates growth, 140. 

Nodes, defined, 76. 

Northerly exposure least trying to 
plants in winter, 120. 

Nursery trees benefited by transplant- 
ing, 73. 

Objects of grafting, 203; of pruning, 237. 
Oedema in plants, caused by excessive 

watering, 129. 
Optimum defined, 24. 
Organic manures, partially decomposed, 

act more promptly than fresh ones, 

143. 
Organic matter, importance of, in 

soil, 65. 
Osmosis defined, 58. 
Ovary, 92. 

Overbearing should be prevented, 99. 
Ovule, 92. 
Oxygen essential to germination, 25; 

necessary to life of roots, 63; source of 

in plants, 42. 

Packing plants for transportation, 222. 

Pales, 94. 

Palets, 94. 

Palisade cells, 47. 

Parasites, animal, 148; defined, 20; flow- 
ering or phanerogamic, 164; fungous, 
165; injurious, 147; vegetable, 164. 

Parenchyma, 49. 

Paris green, 151. 

Pear, blight of, 166, 246. 

Perfect flowers, 97. 

Persian, insect powder, 153. 

Petals, 91. 

Phosphorus, 145; part played by in 
plants, 43. 



Picturesqueness, pruning for, 239. 

Pinching defined, 234; stimulates 
branching, 78; to promote flowering, 
24.4 

Pistil, 92. 

Pith, 50. 

Plant food, elements essential in, 42; 
elements of, likely to be deficient, 43; 
from soil must be dissolved by soil 
water, 42; in soil, reduced by crop 
growing, 141; sources of, 41. 

Plant improvement, reasons for, how 
explained, 249. 

Planting, too close, causes deficient 
light, 137; trees, directions for, 225-227; 
with reference to chance crossings, 
257; with reference to pollination, 97. 

Plantlet, inner structure of, 46; may 
need help to burst seed-case, 33; prin- 
cipal parts of, 39; vigor of, propor- 
tionate to size of seed, 36; visible in 
seed, 38. 

Plant life, round of, 108. 

Plant manipulation, 175; propagation, 
175. 

Plant, directions for lifting the, 219; re- 
moving the, 221. 

Plant tissues, brittleness of, 57; killed 
by drying, 134; toughness of, caused 
by drought, 132. 

Plants, abnormal development of, due to 
insufficient light, 136; affected by un- 
favorable environment, 110; differ- 
ence in water requirments of, 129; 
distance apart for growing, 79; domes- 
tic, defined, 11; have improved under 
culture, 250; heeling-in, 223; injured by 
excessive moisture in the air, 131; in- 
juriously affected by parasites, 147; 
only can assimilate food from mineral 
substances, 41: packing for transpor- 
tation, 222; potted require drainage, 
67; potting and shifting, 229; power of, 
to endure cold, 114; preparation of, for 
replanting, 224; rapid-growing, re- 
quire much water, 128; shading after 
transplanting, 233; those who improve 
are true benefactors, 258. 

Plants under glass liable to suffer from 



272 



Principles of Plant Culture. 



deficient light, 137; need of rest of, 
106: not to be sprinkled in bright 
sunshine. 111; plants, unpacking, 223; 
variability of, 250; washing the roots 
of puddled, !< 24; watering of potted. 67; 
watering recently-transplanted, 233; 
young, screens for shading, 134, 135. 

Plum, black knot of, 166, 246. 

Plum curculio, 162, 163. 

Plumule, 39. 

Poisons, destroying insects by, 151. 

Pollen, 91; appearance of mature, 254; 
applying, 255; to prevent access of un- 
desired, 255. 

Pole shears, 248. 

Pollination, 95; in many plants depend- 
ent on wind, 139; planting with refer- 
ence to, 97, to prevent self-, 254; when 
should it be performed, 255, 256. 

Potash, caustic, 155. 

Potassium, 145; assists in assimilation, 
43; -sulfid solution, 171. 

Potato, ioliage of, injured by sun heat, 
113. 

Potatoes, knobby, 130. 

Potted plants require drainage, 67; wa- 
tering of, 67. 

Potting and shifting, 229; soil, 230. 

Preparation of plants for replanting, 
224. 

Pricking off seedlings, 73. 

Principle of selection, 16, 249. 

Propagating bed, the, 192. 

Propagation by cuttings, 185; by de- 
tached parts, 177, 182; by division, 
176, 177; by division of the crown, 
181; by grafting, 202; by layers, 180; 
by parts intact, 177, 178; by sections 
of the plant, 184; by seeds, 176; by 
specialized buds, 182-184; by stolons, 
179; by suckers, 178; methods of, 175. 

Prosenchyma, 49. 

Protective pruning, 246. 

Protoplasm, active state of, 14; dormant 
state of, 14; some properties of, 14. 

Proximal defined, 76. 

Pruning defined, 234; for density, 
240; for flowers or fruit, 243; for 
growth, 242; for picturesqueness, 239; 



for slenderness, 240; for stockiness, 
239; for strength, 240; for symmetry, 
238; formative, 237; implements. 246; 
insufficient, prevents formation of 
fruit-buds, 137; -knife, 246; matura- 
tive, 246; objects of, 237; protective, 
246; -saw, 247; season for, 235; -shears, 
248; stimulative, 242: where and how 
to make the cut in, 236. 

Psyehrometer, sling, 122. 

Puddled plants, washing roots of, 224; 

Puddled soil defined, 25; prevents ger- 
mination, 26. 

Puddling the roots of trees, 222. 

Pumpkin, provision in, to aid plantlet 
to emerge from seed-case, 32. 

Pyretlirum powder, 153. 

Rabbits, damage from, 148. 

Radicle, 31. 

Raspberry pruning hook, 248. 

Rate of rout growth, 74. 

Reduced vigor, tendencies of, 12. 

Reducing the top of trees prior to plant- 
ing, 224. 

Removing the plant, 221. 

Reproduction defined, 15; relation of to 
growth, 16; sexual and non-sexual, 15. 

Reserve food, 15; how plants use, 61; 
how to promote accumulation of, 88; 
storage of, 60. 

Resin washes, 155. 

Rest period, 105; not peculiar to tem- 
perate zones, 105; plant processes may 
not entirely cease during, 107. 

Reversion, 250. 

Richards' transplanting tools, 228. 

Ring-budding, 213, 216. 

Ringing defined, 235; often causes 
formation of flower-buds, 89. 

Ripening of fruits. 100. 

Root and the soil, 62; office of, 62; orig- 
inates in stem, 62; starvation, 60. 

Root branching, conditions affecting, 71. 

Root branching, how stimulated, 71; 
should be encouraged, 70. 

Root cap, 67. 

Root cuttings, 197. 

Root grafting, 207. 



Index. 



273 



Root grafts, tool for planting, 228. 

Root growth excited by moisture, 62; 
rate of, 74. 

Root-hairs absorb water with consider- 
able force, 70; apply themselves to 
soil particles, 65, 69; dissolve soil par- 
ticles, 69; nature of, 47, 68; show need 
of roots for air, 64. 

Root- killing of trees, 117. 

Root pruning to promote flowering and 
fruiting, 245; stimulates root branch- 
ing, 71, 73. 

Root tubercles, 75. 

Roots, depths of, in soil, 73; destroyed 
by excessive water in soil, 127; growth 
of in length, 67; horizontal extent of, 
73; of trees, puddling, 222; only 
youngest active in absorption, 70; 
oxygen necessary to life of, 63; pro- 
perly and improperly planted, 225; 
relation of, to food supply, 75: replant- 
ing the, 225; start from hypocotyl, 33; 
trimming of, prior to planting, 224; 
washing, of puddled plants, 224; wet- 
ting, prior to planting, 225. 

Root-tip, how penetrates the soil, 67. 

Root-tips, formation of should be en- 
couraged, 70. 

Rosin washes, 155. 

Round of plant life, the, 10S. 

Sacking the roots of trees, 221. 

Saltpeter, 145. 

Sap defined, 44. 

Sap, flow of in spiing, 58. 

Sap-sprouts on fruit trees, 130. 

Saw, pruning, 247. 

Science and art defined, 9; how best 
learned, 10. 

Scientific names, why used, 19. 

Scion, 203. 

Screens for shading young plants, 134, 
135. 

Season for pruning, 235. 

Seed, 98; age of, as affecting the result- 
ing crop, 103; maturing of, injures 
fodder crops, 99; plantlet visible in, 
38; production of exhausts plants, 98; 
selection, importance of, 252; vigor of 
plantlet proportionate to size of, 36; 



vitality, conditions affecting duration 
of, 102. 

Seed-case defined, 22; influence of on 
absorption of water by seeds, 22; in 
germination, 31; is useless after ger- 
mination commences, 32; plantlet 
may need help to burst, 33. 

Seeding, prevention of, prolongs the 
life of plants, 99. 

Seed-leaves defined. 33. 

Seedlings, pricking off young, 73; selec- 
tion of crossed, 256; variation pro- 
duced by growing, 252; young, injured 
by unobstructed rays of sun, 134. 

Seeds absorb water by contact, 21; a few 
germinate in water, 26; drying of, 
how affecting their vitality, 103; ear- 
lier germinating, form more vigorous 
plantlets, 36; gathering and storing 
of, 100; germination hastened by 
soaking, 28; germination hastened by 
mutilating seed-case, 29; how deep 
should they be planted ? 36; immature 
vs. ripe. 101; in which hypocotyl 
lengthens must be planted shallow, 
35; nature of, 15; of pumpkin family 
should be planted flatwise, 33; rate at 
which they absorb water, 21; should 
be tested before planting, 29; should 
not be planted until soil becomes 
warm, 27; stored, moisture an enemy 
to,102; stratification of, 104; very small, 
should not be covered, 37; vitality of, 
limited by age, 101; wny cover, at 
planting, 31; why they fail to germi- 
nate, 29; testing, directions for, 29; 
-tester described, 29. 

Selection a means of fixing variations, 
251; of crossed seedlings, 256; of seed, 
importance of, 252; of subjects for 
crossing, 253; principle of, 16. 

Self pollination, 96. 

Sepal, 91. 

Sexual reproduction, 15. 

Shading plants after transplanting, 233. 

Shears, hedge, 248; lever, 248; pole, 218, 
pruning, 248. 

Shed screen for shading young plants. 
134. 



274 



Principles of Plant Culture. 



Shield budding, 213. 

Shifting and potting, 229. 

Side grafting, 210. 

Sifting box for applying insecticide 
powders, 158. 

Slenderness, pruning for, 240. 

Slips, 198. 

Smut of the small grains, 166. 

Sodium nitrate, 144. 

Soil and the root, 62; a scene of con- 
stant changes, 65; compacting, about 
seeds hastens germination, 27; com- 
pacting wet, may prevent germination, 
26; depth of roots in, 73; how pene- 
trated by root-tip, 67; ideal, for land 
plants, 64; importance of organic 
matter in, 65; needs ventilation, 66; 
particles of, dissolved by root-hairs, 
69; for potting, 230; puddled, defined, 
25; puddled, prevents germination, 26. 

Soil aeration promoted by drainage, 66; 
promotes soil fertility, 143. 

Species, 17. 

Specific names defined, 19. 

Spikelet, 94. 

Splice grafting, 206. 

Splitting down, to prevent branches 
from, 236. 

Spore germination favored by moisture, 
171; prevention of, 166. 

Spores, non-sexual, 16; of ferns, how 
planted, 37. 

Spraying outfit, steam, 160. 

Spray pump, 159. 

Sprinkling of plants under glass to be 
avoided in bright sunshine, 111. 

Squash, provision in, to aid plantlet to 
emerge from seed-case, 32. 

Stable manure, 146. 

Staking trees to prevent snaking by 
wind, 227. 

Stamens, 91. 

Starvation of roots, 60. 

Stem and root development dependent 
on number of leaves, 80. 

Stem defined, 76. 

Stem, fastest elongation of, 78; how 
lengthens, 77; root originates in, 62; 
vital part of woody, 53. 



Stem cuttings, 195; how planted, 197; 
proper length of, 196. 

Stems, how they increase in diameter, 
52; underground, 76. 

Stigma, 92. 

Stimulative pruning, 242. 

Stocks, 203. 

Stockiness, pruning for, 239. 

Stoma defined, 47. 

Stomata defined, 47. 

Storage of cuttings, 194; of reserve food, 
60. 

Stratification of seeds, 104. 

Strawberry, perfect and imperfect flow- 
ers of, 97. 

Strength, pruning for, 240. 

Subjects for crossing, selection of, 253, 

Style, 92. 

Suckering defined, 35. 

Sulfate of potash, 145. 

Sulfur, part played by in plants, 43. 

Sun heat injurious to young seedlings; 
134. 

Sun-scald, 112. 

Superphosphate, 145. 

Symbiosis, 143. 

Table for computing dew point, 123; 

showing duration of seed vitality, 101, 

showing germinating temperatures of 

seeds, 25. 
Tarred-paper cards, tool for cutting, 162. 
T-budding, 213. 
Temperature as affecting plant growth, 

110; fatal to protoplasm, 111; influence 

of on absorption of water by seeds, 22'. 

methods for controlling, 187. 
Tenderness defined, 13. 
Terminal buds, pinching of, effect on 

wood maturity. 119; destruction of, 

by cold, 116. 
Theory of evolution, 20. 
Thermal belts, 126. 
Thinning fruit, 99. 242. 
Time, most favorable for transplanting, 

219. 
Tobacco, broom rape of, 164; decoction 

of, for destroying aphidse, 154; smoke 

for destroying insects, 154; topping. 

242, 246. 



Index. 



275 



Tongue grafting, 206. 

Tool for injecting poisonous liquids, 
161. 

Top grafting, 207. 

Topping defined, 234; tobacco, 242, 246. 

Transpiration, amount of, 56; condi- 
tions affecting, 55; current, 57; de- 
fined, 55; excessive, 56; excessive, 
caused by insufficient moisture in the 
air, 131; increases with degree of heat, 
110. 

Transplanting plants, shading, 233; wa- 
tering, 233. 

Transplanted stock, tardy starting of, 
233. 

Transplanter, Baldridge, 229; Bemis. 
229. 

Transplanting, 218; benefits nursery 
trees, 73; endured best by vigorous 
plants, 218; most favorable time for, 
219; stimulates root branching, 71; 
devices for, 227. 

Transplanting tools, Richards', 228. 

Trapping insects, 150. 

Tree trunks split open by severe freez- 
ing, 117. 

Trees, bundling for transportation, 223; 
detrimental to neighboring crops, 57; 
directions for planting, 226; killing 
by girdling, 59: lifted or lowered to 
accommodate grading, 221; lifting 
large, 220; nursery, benefitted by 
transplanting, 73; puddling roots of, 
222; reducing top of, prior to plant- 
ing, 224; sacking roots of, 221; stak- 
ing, to prevent shaking by wind, 227. 

Trimming defined, 234; roots prior to 
planting, 224. 

Tuber, the, 183. 

Tubercles on roots, 75. 

Turn of the year, 108. 

Underground stems, 76. 

Unhealed wounds introduce decay, 237. 

Unisexual flowers, 97. 

Unpacking plants, 223. 

Variability of offspring of crosses and 

hybrids, 20; of plants, 250. 
Variation, and heredity, 16; how can 

we produce, 252; may take place in 



any direction, 16; produced by cross- 
ing, 253; produced by culture, 252; 
produced by growing seedlings, 252. 

Variations, how to fix desirable, 250 ; 
not always permanent, 250. 

Varieties, 18; origin of cultivated, 249. 

Vascular bundles defined, 49. 

Vegetables, cracks in, caused by exces- 
sive moisture, 130. 

Ventilation, hotbeds require care in 
66; soil needs, 66. 

Veneer grafting, 211. 

Vigor defined, 12; of plantlet propor- 
tionate to size of seed, 36; tendencies 
of reduced, 12. 

Vital part of woody stems, 53. 

Warmth essential to germination, 24. 

Washing the roots of puddled plants, 
224. 

Water, adequate supply of most impor- 
tant, 43; excess of, retards germina- 
tion, 27. 

Water, excessive, in soil destroys roots, 
127; force causing, to rise in stems, 58; 
insufficient, how affecting plants, 131; 
manuring increases capacity of soil 
for, 43; necessary to growth, 43; of 
plants almost wholly absorbed by 
root-hairs, 44; only youngest roots ab- 
sorb, 70; plants contain large amounts 
of, 55; root-hairs absorb, with force, 
70; seeds absorb, by contact, 21. 

Water-sprouts on fruit trees, 130. 

Water supply, unfavorable, the plant as 
affected by, 127. 

Watering, excessive, may produce a 
dropsical condion, 129; copious, at 
intervals preferable to frequent slight 
watering, 129; injudicious, 128; of 
potted plants, 67; recently-trans- 
planted plants, 233. 

Weeds, 172; annual, biennial and per- 
ennial, 172; cause deficient light in 
low-growing crops, 137; how destroy- 
ed, 60; plants as affected by, 172. 

Wet bulb depression, 124. 

Whip-grafting, 206. 

Whole-root grafts, 208. 



276 



Principles of Plant Culture. 



Windbreaks, 120. 

Wind, excessive, effect of, on plants, 
138; insufficient, effect on the plant, 
139; insufficient, promotes damage 
from frost, 139; insufficient, promotes 
development of fungous parasites, 
139; tends to avert frost, 125; unfav- 
orable, how affecting the plant, 138. 



Wood ashes, 145. 

Woodchucks, damage from, 149. 

Wood, darkening of, 116. 

Wood maturity of, favored by a dry soil, 
119; by pinching terminal buds, 119; 
indicated by time of leaf fall, 106. 

Wounds, healing of, 53; unhealed, in- 
troduce decay, 237. 



ERRATA. 



In legend of Fig. 1, for " Protoccus " read Protococcus. In 
the first line of paragraph 48, for " Seeds in which the hypoco- 
tyl lengthens" read Seeds of dicotyledones of which the hypoco- 
tyl lengthens" etc. In the last line of page 35 and the first 
line of page 36, omit " the hypocotyl does not elongate in germi- 
nation, and hence the cotyledon is not lifted, and read " because 
the tiny pointed shoot {plumule) of these plants etc. In para- 
graph 78, next to last line, for " evaportion," read evaporation. 
In legend of Fig. 94, for " Grener,'' read Greiner. On page 
226, third line from top, for "crowed" read crowded. 



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